Ink-Jet System for Protein Crystallization

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DESCRIPTION (provided by applicant): In this project, MicroFab will design and fabricate a prototype ink-jet based protein crystal screening platform (CrystalJet(tm)) with emphasis on membrane proteins that are difficult to crystallize, but critical to cellular function. The prototype platform will perform high-throughput initial protein crystallization screening to identify parameters for subsequent scale-up to diffraction quality crystals. Information for computational and structure based drug development is typically obtained through x-ray diffraction studies of crystallized membrane proteins. However, the crystallization of membrane proteins often fails to produce diffraction quality crystals. Difficulties in crystallizing membrane proteins can be attributed to narrow metastable solubility regions and scarcity of purified protein. A solution to these problems is to decrease protein consumption and narrow the sampling of crystal growth conditions by using smaller screening volumes. Ink-jet dispensing is a technology capable of reliably delivering small volumes ranging from picoliter to microliter, the latter by accretion. The CrystalJet(tm) screening platform will operate in microbatch and vapor diffusion modes to offer experimental flexibility. We will also develop a disposable ink-jet dispenser to address cross contamination issues. A dip-n- sip mode will be developed for the deposition of protein and matching volumes of crystallization/precipitant solution at volumes of <1000 nL. A Cartesian fluid handling system will manipulate larger fluid volumes of >1000 nL, such as oil and well precipitant solutions. The platform will include a plate handler and plate sealer to manipulate and seal crystal-screening plates, environmental control to maintain temperature, humidity and clean air, and a crystal observation and image capture system. A series of screening experiments will be performed using protein standards (e.g., lysozyme, glucose isomerase, thaumatin) and membrane proteins to validate the operation of the CrystalJet(tm) platform. The CrystalJet platform is an automated tool to perform a greater number of protein crystallography screening experiments, while using significantly less protein in comparison to conventional screening systems. Ultimately, this tool will enable faster and more efficient drug target discovery to aid in the development of effective drugs to treat disease.