The Uab Research Foundation

The University of Alabama

Terry L Bray

Lawrence James DeLucas

Michael Hugh Harrington

David T Hamrick

Thomas E Gester

Larry Cosenza

Larry J Kim

A method of screening protein crystal growth conditions with picogram to microgram amounts of protein in picoliter or nanoliter volumes is provided. A preferred method comprises a microarray with a plurality of microchambers in the microarray. A protein solution is placed into the micro-chambers by an automated dispensing mechanism. The protein crystal growth conditions of each of the micro-chambers is adjusted so that the protein crystal growth conditions in at least two of the micro-chambers differs. Crystallization of the protein solution in the micro-chambers is effected. For example, crystallization can be effected by a precipitate solution and/or placing an oil barrier over the protein solution. Protein crystal growth in the micro-chambers is then observed.

Method for screening crystallization conditions in solution crystal growth

An improved method of screening crystal growth conditions is provided wherein molecules are crystallized from solutions containing dyes. These dyes are selectively incorporated or associated with crystals of particular character thereby rendering crystals of particular character colored and improving detection of the dyed crystals. A preferred method involves use of dyes in protein solutions overlayed by oil. Use of oil allows the use of small volumes of solution and facilitates the screening of large numbers of crystallization conditions in arrays using automated devices that dispense appropriate solutions to generate crystallization trials, overlay crystallization trials with an oil, provide appropriate conditions conducive to crystallization and enhance detection of dyed (colored) or undyed (uncolored) crystals that result.

Use of dye to distinguish salt and protein crystals under microcrystallization conditions

A method of screening protein crystal growth conditions on a nano or meso scale comprises providing a micro-electromechanical chip with a plurality of micro-chambers in the micro-electromechanical chip. A protein solution is placed into the micro-chambers by an automated jet type dispensing means with nano or meso scale precision. The protein crystal growth conditions of each of the micro-chambers is adjusted so that the protein crystal growth conditions of each of the micro-chambers differs. Crystallization of the protein solution in the micro-chambers is effected. Protein crystal growth in the micro-chambers is then observed.

Crystal growth can be initiated and controlled by dynamically controlled vapor diffusion or temperature change. In one aspect, the present invention uses a precisely controlled vapor diffusion approach to monitor and control protein crystal growth. The system utilizes a humidity sensor and various interfaces under computer control to effect virtually any evaporation rate from a number of different growth solutions simultaneously by means of an evaporative gas flow. A static laser light scattering sensor can be used to detect aggregation events and trigger a change in the evaporation rate for a growth solution. A control/follower configuration can be used to actively monitor one chamber and accurately control replicate chambers relative to the control chamber. In a second aspect, the invention exploits the varying solubility of proteins versus temperature to control the growth of protein crystals. This system contains miniature thermoelectric devices under microcomputer control that change temperature as needed to grow crystals of a given protein. Complex temperature ramps are possible using this approach. A static laser light scattering probe also can be used in this system as a non-invasive probe for detection of aggregation events. The automated dynamic control system provides systematic and predictable responses with regard to crystal size. These systems can be used for microgravity crystallization projects, for example in a space shuttle, and for crystallization work under terrestial conditions. The present invention is particularly useful for macromolecular crystallization, e.g. for proteins, polypeptides, nucleic acids, viruses and virus particles.

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Birmingham, AL, United States of America

Terry L Bray