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

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 众所周知，蛋白质在常压下受到温度变化时会发生“玻璃化转变”。这一转变涉及蛋白质分子及其酶活性的动态变化。从结晶学的德拜-沃勒因子和蛋白质晶体结构出发，建立了蛋白质动力学与酶活性之间的关系。虽然人们普遍认为蛋白质玻璃化转变与水合水高度相关，但确切的机制仍然缺乏。因此，我们的目标是了解这些确切的机制以及水和蛋白质分子之间的相互作用。在研究的第一步，我们将从两种不同的母液中生长出两种RNaseA晶体，这两种母液对蛋白质分子施加了两种不同的溶剂环境。这些晶体的完整数据集将在从98K到320K的9个温度点上收集(每个点一个完整的数据集)。由于溶剂环境的不同，这两种晶体表现出不同的玻璃化转变行为，这将证实蛋白质动力学与水性质之间的关系。以往的实验表明，我们的RNaseA晶体具有良好的衍射质量。

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.