WO1999042191A1 - Dynamically controlled crystallization method and apparatus and crystals obtained thereby - Google Patents
Dynamically controlled crystallization method and apparatus and crystals obtained thereby Download PDFInfo
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- WO1999042191A1 WO1999042191A1 PCT/US1999/003515 US9903515W WO9942191A1 WO 1999042191 A1 WO1999042191 A1 WO 1999042191A1 US 9903515 W US9903515 W US 9903515W WO 9942191 A1 WO9942191 A1 WO 9942191A1
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
Definitions
- the present invention relates to the formation of crystals of small and large molecules, including macromolecules such as proteins and nucleic acids, and more particularly, to a method and apparatus for dynamically controlling the process of forming such crystals, and the resulting crystals.
- Rational drug design involves obtaining a precise 3-D structure of a specific molecule involved in a disease process, making and studying physical models and computer-generated graphic images of the structure, as well as using sophisticated computer programs that thermodynamically model the structure and its interactions with solvent and other molecules, in order to design drugs that selectively bind to and alter the function of the disease-causing molecule.
- Rational drug design can be used to analyze and design drugs that interact with small molecules such as peptide and non-peptide hormones, as well as intermediate-sized and large macromolecules such as nucleic acids and proteins, respectively.
- the application of rational drag design will result in a number of
- CAPTOPRIL is a well known drug for controlling hypertension that was developed through rational drug design techniques.
- CAPTOPRIL inhibits generation of the angiotension-converting enzyme thereby preventing the constriction of blood vessels.
- X-ray crystallography is a technology that allows us to obtain the precise 3-D atomic structures of molecules such as peptides, proteins, and nucleic acids. A critical step in using X-ray crystallography to determine the 3-D structure of any molecule of interest is establishing a reliable method for crystallizing the molecule.
- Proteins are one of the major classes of structural molecules in living organisms; protein enzymes catalyze the metabolic reactions that make life possible; and many disease processes are mediated by the interactions of proteins with other molecules, including other proteins. Therefore, much time and money have been spent crystallizing proteins for analysis of their structures. Recent biotechnological developments in cloning and over-expression of genes encoding proteins of interest, and also in the purification of proteins, are increasing the need for a reliable way in which to grow protein crystals. Unfortunately protein crystallization is a difficult and unpredictable art.
- Crystallization of a biological molecule such as a protein involves the creation of a supersaturated solution of the molecule under conditions that promote minimum solubility and the orderly transition of the molecules from the solution into a crystal lattice.
- the variables that must be controlled precisely to promote crystal growth include temperature, protein solution concentration, salt solution concentration, pH, and gravitational field, for example (Durbin, S. & Feher, G. Ann Rev Phys Chem 47 (1996) 171-204, the entire contents of which are incorporated herein by reference). These variables are carefully controlled and optimum combinations thereof are determined through experimentation to yield superior crystals.
- the molecule being crystallized e.g., the protein
- a reactant the solution containing one or more precipitants that is used in crystallization processes
- a solution containing one or more precipitants that is used in crystallization processes is referred to as a
- the crystallization process generally involves three distinct phases; nucleation, sustained crystal growth, and termination of crystal growth.
- Nucleation is the initial formation of an ordered grouping of a few reactant molecules and requires a particular concentration of reactant molecules in a precipitating reagent solution.
- the continued growth phase consists of the addition of reactant molecules to the growing faces of the crystal lattice and requires lower concentrations of reagent solution than the nucleation phase.
- the termination phase can be initiated by poisoning the growing lattice with denatured or chemically modified reactant molecules or with different molecules, by depletion of the reactant solution, or by changing the concentration of precipitant to a specified level.
- Robotics enables systematic pipetting of solutions and protein into crystal growth chambers on plates, so that a multiplicity of conditions can be examined more quickly and consistently.
- the use of robotics frees valuable time for researchers.
- Another trend is the use of semi- automated techniques to record results.
- the present invention is a Dynamically Controlled Crystallization System (DCCS) that includes apparatus and methods that can be used to control a molecular crystallization process precisely and dynamically.
- DCCS Dynamically Controlled Crystallization System
- the present invention can further be used to monitor and control a molecular crystallization process remotely in real time.
- the present invention can further be used to control a molecular crystallization process in a predetermined manner.
- the present invention permits initiation, termination or reversal of a molecular crystallization process.
- the present invention permits reduction in the size and number of moving parts in a molecular crystallization method and apparatus.
- the present invention permits production of molecular crystals in a sealed system.
- the present invention can be used to produce molecular crystals under conditions of real and simulated gravity in the range of from about zero times the earth's gravitational field to about 20 times the earth's gravitational field, and to also produce crystals in earth's gravitational field, with identical apparatus.
- the present invention permits crystallization parameters to be controlled in a sealed system without changing the pressure in the crystallization chamber.
- the present invention can be used to optimize the time required to produce large, well-ordered molecular crystals.
- the present invention can be used to optimize crystallization conditions while using less experiments and substantially less reactant, e.g. protein.
- the present invention is "Dynamic control" as used herein means that: (1) the crystallization process can be started at will, (2) several conditions that are important for the growth of molecular crystals, such as pH, conductivity, and temperature, can be measured in the crystallization chamber, (3) decisions regarding altering the conditions affecting crystal growth can be made based upon monitoring crystal nucleation and growth, (4) these conditions can be very precisely controlled at any time during the crystallization process, (5) the crystallization process can be modified or stopped when desired and (6) the process can be reversed if so desired.
- a first aspect of the invention includes at least one crystallization chamber for holding a solution containing reactant molecules that is separated by a permeable membrane from a reagent solution comprising a precipitant at a first concentration, at least one source reservoir comprising reagent solution having precipitant at a second concentration that is coupled via a communication passage with the reagent solution in the crystallization chamber, and at least one drain reservoir that is coupled via a separate communication passage with the reagent solution in the crystallization chamber, and transfer mechanisms configured to respectively transfer reagent solution between the at least one source reagent solution reservoir and the crystallization chamber, and to concurrently transfer reagent solution from the crystallization chamber to the at least one drain resevoir.
- the transfer mechanisms can work in tandem to simultaneously transfer equal amounts of precipitating solution into and out of the crystallization chamber, to thereby alter the concentration of precipitant in the reagent solution in the crystallization chamber with respect to time. In this manner, the concentration of the precipitant in the reagent solution in the crystallization chamber can be adjusted dynamically to provide optimum crystallization conditions with respect to time.
- the invention can also be configured so that two or more pairs of source/drain reservoirs, each containing a different reagent solution, are respectively coupled via separate solution communication means to the reagent solution in the crystallization chamber, with separate solution transfer means to transfer reagent solutions tandemly from the source reservoir to the crystallization chamber, and from the crystallization chamber to the respective drain reservoir, for each pair of reagent reservoirs.
- the paired source and drain reservoirs can be operated sequentially, i.e., one pair at a time, with time allowed for diffusion-mediated mixing of the reagent solution in the crystallization chamber between transfers, so that precipitant concentration in the reagent and reactant solutions in the crystallization chamber is changed in an even, controlled manner.
- the invention also can be configured with two or more crystallization chambers coupled in series via solution communication means, with at least one source reagent solution reservoir being coupled to the reagent solution of the first crystallization chamber in the series, and at least one drain reservoir being coupled to the reagent solution of the last crystallization chamber in the series. Tandem transfer of a volume of reagent solution from a source reservoir to the first crystallization chamber, and from the last crystallization chamber to a drain reservoir, results in transfer of an equal volume of reagent solution from each crystallization chamber in the series to the next one, thereby establishing a concentration gradient of a precipitant in the reagent solution across the series of crystallization chambers.
- the invention can also be configured so that two or more crystallization chambers are coupled via a manifold solution communication means at least one source reagent solution reservoir, and are also coupled via solution communication means, directly or indirectly, to one or more drain reservoirs, so that the same volume of reagent solution can be transferred simultaneously from the source reservoir to each of the two or more different crystallization chambers.
- the invention permits controlled
- the invention thus permits the crystallization process to be controlled easily, merely by operating the transfer mechanisms.
- Another important feature of the present invention is that it has real time remote-controlled operative capabilities, and can easily be used under normal earth gravitational conditions, as well as in environments in which the real or simulated gravitational field is greater or less than earth's gravitational field.
- the invention also permits a complex set of variables in the process of crystal growth to be rigorously examined, manipulated and controlled so that gravity is the only variable. Due to its compactness and ease of operation, the present invention is conservative in terms of cost containment for flights aboard the Space Shuttle and the International Space Station. Use of this invention conserves both money and valuable astronaut time.
- the present invention can remain on a space platform for many sets of experiments, while the crystallization chamber can return to earth with the molecular crystals that are produced in space.
- New chambers, tubing and syringes can be delivered on the next flight pre-loaded. Furthermore, the invention can be readily miniaturized so that it is even more compact than the embodiments shown in the examples disclosed herein, and thus the entire unit can be made even less expensive to transport to and from space.
- the present invention further provides methods for carrying out dynamically controlled crystallization of proteins and other molecules under conditions in which the effective gravitational force resulting from diamagnetism in a high magnetic field (i.e., 16 Tesla or more) is in the range of zero to 20 times earth's gravitational field.
- a high magnetic field i.e., 16 Tesla or more
- Another important feature of the invention is that the apparatus is compact and easily sealed to the air. Sealing the system permits operation without adverse effects on fluid flow and the sieving properties of the dialysis membrane in the crystallization chamber being caused by changes in air pressure. Sealing also prevents contamination of the solutions in the system sample for further experimentation.
- An additional feature of the invention is that it produces crystals in a reduced time with few moving parts and low power requirements.
- Fig. 1 is a detailed schematic view of a crystallization apparatus of the invention.
- Fig. 2 is a schematic illustration of a controller for controlling the crystallization apparatus.
- Fig. 3 is a detailed schematic view of an embodiment of a crystallization chamber in which a dialysis membrane separates reactant solution in a chamber in the top assembly from reagent solution in the lower portion.
- Fig. 4 is a detailed top view of an embodiment of a crystallization chamber, showing attached ionic strength, pH, and temperature probes.
- Figure 5 schematically depicts a series of crystallization chambers that are connected to each other by small diameter tubing, with the first and last crystallization chambers being connected via tubing to source and drain reservoirs
- Figure 6 schematically depicts a row of crystallization chambers connected via manifolds to source and drain reservoirs.
- Figure 7 schematically depicts a 2-D matrix of crystallization chambers, with the crystallization chambers of the rows being connected via manifolds to one pair of source and drain reservoirs, and the crystallization chambers of the columns being connected via manifolds to a different pair of source and drain reservoirs.
- Figure 8 schematically depicts a series of crystallization chambers in the bore of a magnet capable of generating effective gravitational fields of from between 0 to
- the present invention comprises an apparatus and method for producing molecular crystals that permits the monitoring of crystal growth and dynamic control of the crystallization conditions so that large, high quality crystals are produced in a relatively short times.
- the methods and apparatus of the present invention can be used to crystallize molecules ranging in size from small organic compounds of about 10-30 atoms up to large macromolecular complexes comprising tens of thousands of atoms.
- the description that follows often refers to using the method and apparatus of the present invention to crystallize a protein; however the methods and apparatus described herein can be used with equal success to crystallize molecules other than proteins, such as small organic molecules and medium-sized molecules such as oligonucleotides and oligopeptides.
- reactant refers to the molecule that is being crystallized.
- precipitant and reagent refer to chemical compounds which affect the solubility of the molecules being crystallized and which,
- reagent solution refers to a solution comprising one or more precipitants.
- Fig. 1 illustrates protein crystallization apparatus 10 in accordance with the invention.
- Apparatus 10 includes rigid base plate 12, crystallization chamber 14 in which crystallization is to occur, syringe 16, syringe 18, lead screw 22, yoke 24, and guide rods 26 and 28.
- Solution containing the reactant molecules to be crystallized is removably disposed inside crystallization chamber 14.
- Syringe 16 is coupled to crystallization chamber 14 by tube 17 serving as a conduit.
- Syringe 18 is coupled to crystallization chamber 14 by tube 19 serving as a conduit.
- Syringes 16 and 18 serve as reagent solution reservoirs as described in detail below.
- Plungers of syringe 16 and syringe 18 face in opposing directions and are coupled to yoke 24 which serves as an interlock as described below. Further, yoke 24 is disposed so that it slides on guide rods 26 and 28.
- Lead screw 22 is coupled to a shaft of motor 20 via aligning coupling 21 and is engaged with yoke 24 via a threaded bushing.
- Syringe 16, syringe 18, guide rod 26 and guide rod 28 are fixedly coupled to base plate 12 by mounting blocks 30 and screws 31 as shown.
- Mounting block 32 is fixed to base plate 12 by screws 31 and has a bearing for permitting rotation of lead screw 22 while axially fixing lead screw 22 to base plate 12.
- crystallization chamber 14 and stepper motor 20 are also fixed to base plate 12 by screws 31.
- Spring 29 is coupled to base plate 12 by screw 31 at one end and to yoke 24 at another end to bias yoke 24 in one direction against threads of lead screw 22 to thereby minimize backlash when yoke
- the reactant molecules that can be crystallized by the present invention include, but are not limited to, macromolecules such as proteins, nucleic acids in combination with proteins, proteins bound to lipids and glycolipids. If the reactant molecules are membrane-bound proteins, a detergent can be introduced into the reactant molecules.
- the reactant molecules can also be small molecules such as drug molecules, co-factors, amino acids, nucleotides, hormones and other signaling and regulatory molecules, and analogs of the foregoing.
- Medium-sized molecules that can be crystallized by using the present invention include, but are not limited to, peptides, protein fragments, and oligonucleotides. Large macromolecular complexes such as viruses can also be crystallized using the present invention.
- Crystallization chamber 14 comprises a system for retaining the reactant molecules, but allowing for the passage of smaller molecules.
- a permeable membrane, porous diaphragm, or permanent sieve, having a molecular weight cut-off of a predetermined value may be used as in this regard.
- the membrane may be a dialysis bag or a sheet of dialysis membrane.
- the molecular weight cut-off should be lower than the molecular weight of the reactant molecules in the crystallization chamber, and should significantly reduce movement of the reactant molecules out of the crystallization chamber.
- the membrane or sieve should not significantly hinder the movement of smaller precipitant molecules, e.g., ions and non-ionic solutes.
- a solution containing reactant macromolecules to be crystallized is loaded into a dialysis sack 15, which is placed directly into the crystallization chamber for retention of the macromolecules, and reagent solution is disposed around the dialysis sack 15 to completely fill the crystallization chamber, as shown schematically in Figure 1.
- the crystallization chamber comprises a sieving membrane such as a dialysis membrane that separates the crystallization chamber into two compartments, one of which contains a reactant solution, and the other of which contains a reagent solution.
- the crystallization chamber can comprise a top cover that includes a recessed portion; the cover itself may be recessed for this purpose, or the cover may comprise a button-shaped protrusion that is recessed for this purpose.
- the cover comprises a recess that serves as a compartment into which is put solution containing reactant molecules for crystallization. The recess is then covered by a membrane as described above.
- Transparent top cover 40 comprising a cylindrical protusion is fitted onto inside cover 41 with the center protusion of cover 40 fitting into the central hole and partially through the hollow cylindrical protusion of cover 41 to form recession 42, and is secured in place with three screws.
- Recession 42 is filled with reactant solution containing the molecule to be crystallized, and the opening is covered with dialysis membrane 43 that is held in place with an O-ring 44.
- the opening at the bottom of the perforated, cylindrical protusion of inside cover 41 is obturated with a dialysis membrane 43 that is held in place with an O-ring 44, and reservoir 45 in the lower portion of the crystallization chamber 46 is filled with the desired reagent.
- the inside cover is then placed on the lower portion 46 so that the exposed surface of the dialysis membrane is fully in contact with the reagent solution and there are no air bubbles in the crystallization chamber, and the inside cover is secured in place with three screws.
- Reactant solution e.g., a solution containing a protein to be crystallized
- Reactant solution is added through the hole in the top of the inside cover to the recess having as its base the upper surface of the dialysis membrane.
- Transparent top cover 40 is then placed on the inside cover with the center protusion fitting into the central hole of the inside cover, and is secured in place with three screws.
- Cover seals 47 prevent solution from leaking out of the chamber.
- the volume of recession 42 that is formed when the two covers are assembled is determined by the diameter of the hole through the inner cover, and the difference in the length of the hollow cylindrical protusion extending from the inner cover and the length of the solid cylindrical protusion extending from the top cover.
- the volume of recession 42 can range from about 10 microliters to 500 microliters or more.
- the volume of recession 42 is about 50 microliters
- the volume of reagent solution reservoir 45 is one ml.
- the invention also includes other ways to retain the reactant molecules in the crystallization chamber that will be readily apparent to those skilled in the art.
- reagent solution is loaded into syringe 16, and optionally into syringe 18 also.
- Each of the reagent solutions that are used in the crystallization chamber and syringes can contain one or more of any precipitants having ionic or chemical characteristics that, at the appropriate concentration, permit crystallization of the protein.
- the relative concentrations of reagent solution in the crystallization chamber(s) and in the solution chambers can be varied, based on crystallization conditions.
- the apparatus and method of the present invention are used to raise or lower the concentration of reagent solution in the crystallization chamber(s) to a desired value for crystallization.
- Fig. 1 shows tubing 17 and 19 from syringes 16 and 18, respectively, making connection to the same side of crystallization chamber 14, and Fig. 3 shows the tubing from the source and drain reagent solution reservoirs making connection to opposite sides of the crystallization chamber.
- Figure 3 has a cutaway view in which the threaded insert of the inlet tube 48 is shown.
- the simultaneous, opposing motions of the plungers in the two syringes causes one syringe to inject a drop of reagent solution into the reagent reservoir of the crystallization chamber while the other syringe withdraws an equal volume of solution from the same reservoir.
- activation of motor 20 in a direction causing yoke 24 to move in the direction of arrow X shown in Figure 1 will cause reagent solution stored in syringe 16 to be transferred into crystallization chamber 14
- the concentration of precipitant in the reagent solution resulting in crystal formation is known, the respective concentrations of precipitant in the reagent solutions in crystallization chamber 14, syringe 16, and syringe 18, can be set to the appropriate different values prior to crystallization, and the concentration of precipitant in the reagent solution in crystallization chamber 14 can be controlled with respect to time by operating motor 20 in a desired manner over time.
- the optimal time period for dynamically adjusting the precipitant concentration in the crystallization chamber to a concentration giving crystals of the desired size can then be determined empirically.
- crystallization chamber 14 and syringe 18 can initially contain reagent solutions comprising precipitant at a concentration that is sufficiently high that crystallization does not occur (1 M salt, for example), and syringe 16 can initially contain a reagent solution comprising precipitant at a concentration that is lower than the concentration that permits crystallization (0.1 M salt, for example).
- motor 20 can be activated to move yoke 24 in the direction of arrow X in Fig. 1, to thereby transfer a small amount of low concentration reagent solution from syringe 16 into crystallization chamber 14 and simultaneously transfer high concentration reagent solution from crystallization chamber 14 into syringe 18. It can be seen that this procedure lowers the concentration of the precipitant in crystallization chamber 14.
- Motor 20 can be activated in desired increments in a pre-programmed manner to change the concentration of the solution in crystallization chamber 14 to a desired value over a selected period of time.
- sensors are placed in the crystallization chamber, in the syringes, or at appropriate positions to detect solution concentration, temperature, position, pressure or other variables, and one or more monitoring systems are used to monitor crystal nucleation and growth in the
- the concentration of precipitant in crystallization chamber 14 can be finely adjusted and raised or lowered to a value which will stop, or even reverse, the crystallization process, thereby giving precise dynamic control of the crystallization process.
- motor 20 can be a stepper motor (e.g., Model No. STP42 ND 4BLVE-100 manufactured by EPSON AMERICAN).
- controller such as a digital or analog programmable controller, that facilitates predetermined programmable control of the crystallization process, as described below, can be used to control motor 20 (e.g, the MTSD-V1 motor driver, manufactured by MODERN TECHNOLOGY, INC.).
- all components, including the motor and controller may have to be certified or approved by the appropriate regulatory authority.
- Fig. 2 is a schematic illustration of controller 40 for controlling motor 20 and thus the crystallization process.
- Controller 40 is constituted of control circuit 50, input connector 60, programming terminal 70, display 80, output connector 90, and input connector 100.
- Control circuit 50 includes CPU (central processing unit) 52, I/O circuit 56, clock 54, and memory 53.
- Control circuit 50 can be a conventional microprocessor based device, such as a personal computer or an industrial programmable controller, or control circuit 50 can be a dedicated solid state, hardwired, digital, analog or mechanical controller, for example.
- Clock 54 generates pulses at regular intervals in a conventional manner to provide timing for the operation of the other components.
- Memory 53 contains operating instractions for
- the operating instructions can be in
- I/O circuit 56 provides an interface between CPU 52 and external components such as motor 20, programming terminal 70, display 80 and any sensors or actuators.
- Input connector 60 includes three input connections for motor voltage (+M) a 5 volt D.C. logic voltage (+5), and a ground (G). Input connections of connector 60 are coupled to I/O circuit 56.
- Output connector 90 includes output connections for a first winding of motor 20 (Ml), a second winding of motor 20 (M2) and ground (G). Output connections of connector 90 are coupled to I/O circuit 56 and to stepper motor 20 at (a) (as indicated in Figs. 1 and 2.)
- Programming terminal 70 is coupled to CPU 52 through I/O circuit 56 to permit operating instructions to be input into the memory 53 of CPU 52. Programming terminal 70 can consist of any input device such as a keyboard, a touch screen, a bank of switches, push buttons, or the like. Once the operating instructions are stored in memory 53, programming terminal 70 can be disconnected from I/O circuit 56 or can remain connected to I/O circuit 56.
- Display 80 also is coupled to CPU 52 through I/O circuit 56 and serves to display operating parameters or status relating to the operation of controller 40.
- display 80 can be a CRT, LCD display, LED display or similar device.
- display 80 is optional.
- the proper input voltage is supplied to input connector 60 and output connector 90 is coupled to stepper motor 20, controller 40 can control motor 20 to operate in a predetermined manner with respect to time to thereby control the crystallization process in a desired manner.
- controller 40 can control motor 20 to operate in a predetermined manner with respect to time to thereby control the crystallization process in a desired manner.
- the operating instructions stored in memory 53 can be configured to control the crystallization process; i.e. the concentration of precipitant in crystallization chamber 14 in a dynamic manner with respect to time to provide desirable crystallization conditions
- Input connector 100 includes inputs I,-I 4 for coupling additional inputs, such as limit switches, sensors, and the like, to CPU 52 through I/O circuit 56. This permits closed-loop control to be achieved, based on the state of the crystallization process or other variables. Additionally, these inputs can be coupled to switches, or the like, for initiating, terminating, interrupting or changing the operation of CPU 52.
- operating instructions stored in memory 53 can be programmed in accordance with any desired operation and external inputs or outputs.
- one or more sensors can be attached to the crystallization chamber to provide feedback to permit closed loop control.
- a sensor which measures the electrical resistance or other electrical properties of a salt solution in crystallization chamber 14 can be used to indicate the concentration of the solution in the crystallization chamber, because electrical properties of the salt solution change as the concentration changes.
- Additional sensors which measure pH and temperature of the reagent solution in the crystallization solution can also be attached to crystallization chamber 14. Sensors that measure ionic strength and pH which are suitable for use in the present invention can be obtained, for example, from Microelectronics, Inc., 40 Harvey Rd., Bedford, NH.
- FIG. 4 is a top view of a preferred embodiment of a crystallization chamber of the present invention, showing the configuration for the attachment of a pH reference probe 62, a conductivity probe 63, a pH measurement probe 64, and a temperature probe 65.
- the inlet tube 66, outlet tube 67, and screws 68 securing the top of the crystallization chamber are also shown.
- Fig. 1 schematically illustrates an embodiment of the apparatus of the present invention comprising a single crystallization chamber 14 to which is attached an ionic strength sensor 33, a pH, sensor 34, and a temperature sensor 35.
- Leads 36, 37, and 38 connect the sensors to ionic strength, pH, and temperature probes that are in contact with the reagent solution in crystallization chamber 14.
- Output lines 56, 57, and 58 carry ionic strength, pH, and temperature information to the controller (40 in Fig. 2), and correspond to one or more of the inputs I,-I 4 shown in Fig. 2.
- crystal nucleation and growth in the crystallization chamber are monitored by any of the methods known to those in the art of growing molecular crystals.
- the crystallization chamber can have a transparent cover, and crystal nucleation and growth can be monitored by looking at the contents of the reagent reservoir or dialysis sac within the crystallization chamber with an appropriate magnifying device; e.g., a microscope.
- Viewing and visual recording devices to image the interior of the crystallization chamber 14 are not shown; however, such devices are commonly used to evaluate crystal nucleation and growth, and can readily be employed with the present invention by one skilled in the art.
- Such devices may include, but are not limited to, a camera to take static photographs, a video-recording device, a magnifying device, and a magnifying device in tandem with a video-recording device.
- early crystal growth can be detected by directing fiber optic leads to the reagent solution that direct light into the solution and measure the light scattering (for example, see Durbin & Feher, 1996, p. 184).
- the crystallizing protein comes out of the reactant solution, it changes the electrolytic properties of the reagent solution.
- nucleating crystals can be detected by introducing conductive wires into the reagent solution that function as the plates of a capacitor.
- syringes are used to store reagent solutions, and plungers of the syringes are moved by a yoke to transfer the reagent solutions into and out of the crystallization chamber(s).
- each pair of syringes can be coupled to a different motor-driven yoke so that it can be operated independently of the others.
- any arrangement for delivering reagent solution to and from the crystallization chamber(s) can be used.
- two or more reservoirs each pair having pumps which are electrically or mechanically interlocked, can be used, or a single reservoir or syringe c-an be used and any excess reagent solution can be allowed to drain into a reservoir or the atmosphere, or a valve arrangement can be used.
- Any solution communicating means can be used as the solution conduits that direct
- reagent solution between the reagent solution reservoirs and the crystallization chamber; for example, plastic, glass, or metal tubing, or a fluid-transporting channel in a chip (e.g., silicon), would be suitable for the present invention.
- Any mechanism can be used to coordinate transfer of reagent solution to and from the crystallization chamber(s), such as a software interlock programmed into the controller or any other mechanical interlock.
- the reagent solution can be transferred to a test tube, beaker, or other suitable container, into which is placed a dialysis bag filled with a solution containing the molecule to be crystallized.
- test tube beaker, or other suitable container can then function as the above-described crystallization chamber, with the selected reagent solutions being pumped or injected into and out of the solution holding the dialysis bag, to dynamically alter the composition of the solution surrounding the dialysis bag to one which produces crystals.
- the apparatus of the present invention can include multiple, independently controlled sets of syringes that are attached to a crystallization chamber.
- a first set of syringes can be attached to a crystallization chamber to deliver a solution containing a precipitant that is appropriate for promoting nucleation and crystal growth
- a second set of syringes can be attached to the same crystallization chamber to deliver a solution containing a salt that is appropriate for stabilizing and storing the crystal for a prolonged period of time.
- fluid from the second set of syringes can be admitted into the reagent reservoir in the crystallization chamber through a very narrow bore access tube ( ⁇ 0.2mm) or other suitable outlet, while an equal volume of fluid from this area may be concurrently pumped out of this area of the chamber through a very narrow bore access tube ( ⁇ 0.2mm) or other suitable outlet, until the desired concentration of stabilizing salt solution in the crystallization chamber is attained.
- the apparatus having a single crystallization chamber is also useful for comparing crystal growth under diverse conditions; for example, in different gravitational fields, or at different temperatures.
- crystallization conditions giving well-ordered crystals for a given protein or other molecule are often unknown, or have not been optimized.
- embodiments of the apparatus of the present invention that comprise multiple crystallization chambers and that are capable of varying multiple solution parameters in the different crystallization chambers can be used to identify conditions that promote growth of good crystals.
- Figure 5 schematically depicts a series of crystallization chambers that are connected to each other by small diameter tubing, with the first and last crystallization chambers being connected via tubing to syringes containing reagent solutions of selected concentration.
- Fig. 5 correspond to, and serve the same function as, syringes 16 and 18 in Fig. 1.
- all of the crystallization chambers in the series initially contain identical reactant and reagent solutions.
- an equivalent volume of solution is transferred from each cell into the tubing leading "downstream" to the next, adjacent cell, in the series, and from the last cell to the drain syringe.
- Each drop of reagent solution containing a high concentration of precipitant that is injected from the source syringe mixes with the reagent solution in the first cell and is diluted, so that the reagent solution that is transferred from the first cell to the second cell has a lower concentration of precipitant than the drop which was injected into the first cell.
- the dilution of transferred reagent solution occurs in each subsequent cell in the series in like manner. Accordingly, the rate at which the concentration of precipitant increases is greatest in the crystallization chamber adjacent to the source reservoir, and is successively lower in each successive chamber in the series. To have full control of the precipitant concentrations in the cells, it is important that the reagent solutions do
- FIG. 6 schematically depicts an embodiment in of the invention in which reagent solution is transferred from a source reservoir via a manifold to multiple crystallization cells, each of which can have vary in their initial reactant and/or reagent solutions.
- crystallization processes can be monitored in a set of crystallization chambers having different initial conditions as the concentration of one or more precipitants is varied simultaneously in all of the cells in a coordinate manner.
- the present invention also includes configuring crystallization chambers in two- and three-dimensional matrices according to the teachings described above, in order to analyze crystallization under a large number of different, dynamically controlled conditions.
- Figure 7 schematically depicts a 2-D matrix of crystallization chambers through which two different solutions, each containing one or more precipitants, are pumped in different directions to produce independently controlled concentration gradients of the precipitants across the rows and columns of cells.
- Each source and drain syringe is operated in tandem, and the different source/drain pairs are operated sequentially.
- Cross-flow between cells is prevented by using small bore tubing to connect the cells, and if necessary, valves in the lines between the cells which only open when fluid is being transferred.
- the effects on crystallization of varying the concentration of one or more additional precipitants in multiple crystallization chambers can be observed by connecting the crystallization chambers of two or more matrices, e.g., in a "stack," to form a third dimension across which one or more gradients of precipitant concentration is established.
- the source and drain syringes controlling flow of the additional reagent solutions into crystallization chambers of the first matrix, and out of chambers of the last matrix are operated in tandem, and are operated sequentially with respect to the other sets of syringes, in the manner described above for syringes in the 2-D matrix.
- the methods of the present invention permit and include controlling the physical parameters that can influence or promote crystal growth, or improve the quality of the crystals that are grown.
- temperature is an important physical parameter affecting crystal growth
- the present invention includes use of a device to control temperature of the solutions in the crystallization chamber.
- a device for controlling the crystallization temperature include a Peltier cooler, a temperature controlled container, and heating coils imbedded in the system.
- Example 2 describes the successful operation of the present invention in producing protein crystals in the microgravity environment of space.
- the apparatus of the present invention can be spun by a centrifuge in space to subject the reactant molecules in the crystallization chamber to gravitational forces that are greater than the microgravity present in space, but less that normal earth gravity.
- a centrifuge can be used in space or on earth to subject the reactant molecules in the crystallization chamber to a gravitational force that is greater than normal earth gravity.
- diamagnetism causes the electrons of molecules in the field to experience a force of repulsion or attraction that is dependent on the strength of the magnet and the distance of the molecules from the center of the magnet.
- the matter When moved to different positions with respect to the center of the magnet, the matter experiences effective gravitational forces that range between zero and normal earth gravity.
- the matter experiences effective gravitational forces ranging from
- each crystallization chamber consists of a reactant reservoir of about 1 ml volume which communicates with the reagent chamber (a few mm 3 volume) through a dialysis membrane, as described previously.
- a high field magnet e.g. 16T
- each crystallization chamber is at a different g eff value, and also a different magnetic field value.
- the first crystallization chamber 71 shown in Fig. 8 is connected to a reagent solution source reservoir by inlet tube 74. Small-diameter tubing connects each of the crystallization chambers to the next one in the series, and the last chamber in the series is connected to a drain reservoirs by return tube 75. This configuration of crystallization chambers is similar to that shown in Fig. 5.
- a concentration gradient of precipitant can be established across the series of crystallization chambers.
- the gg ff 0 condition cannot be maintained, but a finer variation for the condition 2g ⁇ g gff ⁇ g can be obtained.
- the magnet is a water-cooled resistive magnet
- the controller can adjust the temperature of the magnetic bore to temperatures between 10 and 40°C once it reaches a steady state, to give control over an additional physical parameter affecting crystal growth.
- the magnet is a superconducting magnet that is kept cold in a cryogenic container, similar to the magnets used by nuclear magnetic resonance (NMR) spectroscopists or clinical magnetic resonance imaging (MRI) specialists, for which access to the magnetic field region of interest is at a temperature selected by the controller; e.g., room temperature.
- NMR nuclear magnetic resonance
- MRI clinical magnetic resonance imaging
- Ribonuclease S were grown both on earth at lg, and in the microgravity environment
- the protein was disposed in a dialysis bag in 50 microliters of solution of 1.2M LiCl at a pH of 7.5 at a protein concentration of 12 mg/ml.
- the dialysis bag was then placed in the crystallization chamber and the remainder of the crystallization chamber was filled with a 1.2M solution of LiCl at pH of 7.5.
- One of the syringes was loaded with a 0.1M solution of LiCl at pH of 7.5 which was injected into the crystallization chamber.
- Several trials were conducted under these initial conditions with the amount of salt solution transferred from the syringe to the crystallization chamber being different in each trial. In each trial, the amount of salt solution transferred from the crystallization chamber was equal to the amount of salt solution transferred to the crystallization chamber, as described above.
- trials 1 and 2 did not lower the concentration of the salt solution in the crystallization chamber enough to produce large crystals.
- trials 3-5 larger amounts of low concentration salt solution were transferred into the crystallization chamber and thus the concentration of salt solution was lowered into a range in which the protein can come out of solution to form large crystals.
- the results of trials 3-5 compared favorably to a control trial using a conventional dialysis method of crystallization.
- a 50 ⁇ l dialysis bag was filled with CPA at a concentration of 12 mg/ml in 1.2M LiCl at a pH of 7.5.
- the dialysis bag was filled with CPA at a concentration of 12 mg/ml in 1.2M LiCl at a pH of 7.5.
- Ribonuclease S protein was purchased from Sigma chemical company. The protein was dissolved to a concentration of 24 mg/ml in a solution of 25% ammonium sulfate, 25% sodium chloride, 0.1 M Na-acetate, pH 5.0, and was dialyzed against the same solution overnight. At this concentration, protein crystallization begins at about 75% total salt saturation of the precipitant solution.
- Controlled Crystallization System of the present invention, and through vapor diffusion in hanging drops. All solutions included a standard 25% saturated ammonium sulfate and 0.1 M Na-acetate, pH 5.0. In all cases, the only precipitant that was varied was sodium chloride. Crystallization generally occurs when the concentration of NaCl reaches 47-52% saturation.
- the preliminary hanging drop trials were carried out in linbro plates from Hampton research. The reservoirs were filled with solution containing precipitant at concentrations expected to give precipitation. They were made by mixing 250 microliters of saturated ammonium sulfate, 40 microliters 2.5 M Na-acetate, 470-600 microliters of saturated NaCl, and water to 1 ml volume.
- the amounts of NaCl were selected to scan a broad range, to find the value that gave the best crystals.
- the hanging drops were formed by mixing equal 5-microliter volumes of protein solution and reservoir solution on a siliconized coverslide, also from Hampton Research. The drops were kept at room temperature (24° C). The process of vapor diffusion in a sealed system gradually increased the salt concentration in the drop to the level in the reservoir, and nucleation occurred.
- the source syringe was filled with the precipitant solution at the expected level of crystallization.
- the reservoir was filled with a lower level of a similar solution. It would include the standard ingredients and only 35-40% sodium chloride. This concentration is too low to nucleate Ribonuclease S crystals.
- the mission length of STS-95 was 10 days.
- the computer program ran and syringes moved for the first 3.5 days of the mission. Accordingly, the solution containing the protein would take 3.5 days to reach the expected nucleation point, and the remainder of the time the crystals could continue to grow.
- the DCCS units were then shipped from Florida to the Center for Advanced Research in Biotechnology (CARB) in Gaithersburg, MD, and opened there.
- the crystals were counted through the membrane using a microscope.
- the crystals were first photographed with a Nikon FX camera through the dialysis membrane, while remaining in their growth environment. This allows comparison of where in the chamber they grew and their appearance before being moved in the event damage occurs during that process.
- the procedure involved removing them from the original protein chamber and placing them in artificial mother liquor in hanging drops.
- the mother liquor solution consisted of 60%) sodium chloride,
- Crystals that were free floating in the growth chamber were simply inverted onto a coverslide and poured out of the chamber. However, those that had grown stuck to the various walls of the chamber and to the membrane had to be gently detached from the surface with a fiberloop and physically placed into hanging drops. At his point the crystal sizes were measured using a microscope. Morphology and defect observations were also made and documented. Photographs were then taken again while in this hanging drop environment with the same camera and later transferred into digital image files. Once well documented on film and stabilized in solution, the crystals were mounted in 1.0 mm, siliconized glass capillaries for X-ray diffraction analysis.
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- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
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Abstract
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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EP99914879A EP1059976A4 (en) | 1998-02-18 | 1999-02-18 | Dynamically controlled crystallization method and apparatus and crystals obtained thereby |
AU33529/99A AU3352999A (en) | 1998-02-18 | 1999-02-18 | Dynamically controlled crystallization method and apparatus and crystals obtained thereby |
JP2000532196A JP2002503538A (en) | 1998-02-18 | 1999-02-18 | Kinetic controlled crystallization method and apparatus and crystals obtained by them |
US09/622,553 US6596081B1 (en) | 1998-02-18 | 1999-02-18 | Dynamically controlled crystallization method and apparatus and crystals obtained thereby |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US09/025,475 | 1998-02-18 | ||
US09/025,475 US5961934A (en) | 1998-02-18 | 1998-02-18 | Dynamically controlled crystallization method and apparatus and crystals obtained thereby |
IL128216 | 1999-02-15 | ||
IL12821699 | 1999-02-15 |
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WO1999042191A1 true WO1999042191A1 (en) | 1999-08-26 |
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EP (1) | EP1059976A4 (en) |
JP (1) | JP2002503538A (en) |
AU (1) | AU3352999A (en) |
WO (1) | WO1999042191A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008214348A (en) * | 2000-12-18 | 2008-09-18 | Cubist Pharmaceuticals Inc | Method for preparing purified lipopeptide |
US8697638B2 (en) | 2000-12-18 | 2014-04-15 | Cubist Pharmaceuticals, Inc. | Methods for preparing purified lipopeptides |
CN115924995A (en) * | 2022-12-29 | 2023-04-07 | 合肥综合性国家科学中心能源研究院(安徽省能源实验室) | Preparation method of multi-element anode material with gradient composite structure |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2001251218B2 (en) * | 2000-03-31 | 2006-06-29 | Perkinelmer Health Sciences, Inc. | Protein crystallization in microfluidic structures |
JP4910121B2 (en) * | 2002-08-16 | 2012-04-04 | 独立行政法人産業技術総合研究所 | Partial suppression of convection |
KR102252029B1 (en) * | 2019-07-26 | 2021-05-14 | 주식회사 한국바이오 셀프 | Apparatus for micro particle treatment |
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US4263010A (en) * | 1979-10-31 | 1981-04-21 | University Patents, Inc. | Control method and apparatus for crystallizer process control |
US4755363A (en) * | 1985-10-30 | 1988-07-05 | Fujitsu Limited | Automated biopolymer crystal preparation apparatus |
US4919900A (en) * | 1987-01-21 | 1990-04-24 | Aerospatiale Societe Nationale Industrielle | System for crystal growth, particularly for space vessel |
US5362325A (en) * | 1990-10-25 | 1994-11-08 | Fujitsu Limited | Apparatus for growing crystals in an environment in which opportunity for accessing is limited |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2631558B1 (en) * | 1988-05-18 | 1992-01-10 | Aerospatiale | CRYSTALLOGENESIS APPARATUS, ESPECIALLY FOR A SPACE VESSEL |
US5643540A (en) * | 1995-02-27 | 1997-07-01 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Protein crystal growth apparatus for microgravitiy |
-
1999
- 1999-02-18 AU AU33529/99A patent/AU3352999A/en not_active Abandoned
- 1999-02-18 WO PCT/US1999/003515 patent/WO1999042191A1/en not_active Application Discontinuation
- 1999-02-18 JP JP2000532196A patent/JP2002503538A/en not_active Withdrawn
- 1999-02-18 EP EP99914879A patent/EP1059976A4/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4263010A (en) * | 1979-10-31 | 1981-04-21 | University Patents, Inc. | Control method and apparatus for crystallizer process control |
US4755363A (en) * | 1985-10-30 | 1988-07-05 | Fujitsu Limited | Automated biopolymer crystal preparation apparatus |
US4919900A (en) * | 1987-01-21 | 1990-04-24 | Aerospatiale Societe Nationale Industrielle | System for crystal growth, particularly for space vessel |
US5362325A (en) * | 1990-10-25 | 1994-11-08 | Fujitsu Limited | Apparatus for growing crystals in an environment in which opportunity for accessing is limited |
Non-Patent Citations (1)
Title |
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See also references of EP1059976A4 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008214348A (en) * | 2000-12-18 | 2008-09-18 | Cubist Pharmaceuticals Inc | Method for preparing purified lipopeptide |
US8697638B2 (en) | 2000-12-18 | 2014-04-15 | Cubist Pharmaceuticals, Inc. | Methods for preparing purified lipopeptides |
US8796224B2 (en) | 2000-12-18 | 2014-08-05 | Cubist Pharmaceuticals, Inc. | Methods for preparing purified lipopeptides |
US8846610B2 (en) | 2000-12-18 | 2014-09-30 | Cubist Pharmaceuticals, Inc. | Methods for preparing purified lipopeptides |
CN115924995A (en) * | 2022-12-29 | 2023-04-07 | 合肥综合性国家科学中心能源研究院(安徽省能源实验室) | Preparation method of multi-element anode material with gradient composite structure |
Also Published As
Publication number | Publication date |
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AU3352999A (en) | 1999-09-06 |
EP1059976A1 (en) | 2000-12-20 |
JP2002503538A (en) | 2002-02-05 |
EP1059976A4 (en) | 2001-02-28 |
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