DYNAMICS OF PROTEIN RNASE A & WATER-PROTEIN INTERACT AT DIFFERENT TEMPERATURES

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Proteins are known to undergo `glass transition` when subjected to temperature variations at ambient pressure. This transition involves dynamics of protein molecules and their enzymatic activity. From crystallographic Debye-Waller factors and protein crystal structures, the relation between protein dynamics and enzymatic activity was established. Though it is widely accepted that protein glass transition is highly related to the hydration water, the exact mechanisms are still lacking. Therefore, our aim is to understand these exact mechanisms and the interactions between water and protein molecules. In the first step of the study, we will grow two kinds of RNase A crystals from two different mother liquors which impose two different solvent environments to protein molecules. The complete dataset for these crystals will be collected at 9 temperature points ranging from 98 K to 320 K (one complete dataset for each point). These two kinds of crystals are expected to exhibit different glass transition behaviors due to different solvent environments, which will confirm the proposed relation between protein dynamics and water properties. The previous experiments showed our RNase A crystals have good diffraction quality.