Minority PreDoctoral Fellowship Program

描述（由申请人提供）： 蛋白质的氨基酸序列决定其折叠。然而，小的变化，如单个氨基酸取代或缺失，可导致错误折叠，和随后的聚集。蛋白质错误折叠直接导致几种毁灭性的人类疾病。分子伴侣有助于许多蛋白质的折叠，特别是那些易于错误折叠和聚集的蛋白质。然而，分子伴侣如何区分错误折叠的蛋白质和高效折叠的蛋白质还不清楚。将研究主要细菌伴侣复合物GroEL/ES的底物特异性机制。该提案的主要目的是选择和表征GroEL/ES的突变体，其更有效地折叠底物蛋白。噬菌体P22的外壳蛋白将是用于分离分子伴侣突变体的模型底物，因为几个单个氨基酸取代将外壳蛋白转化为GroEL/ES的底物，尽管效率有限。将选择能够在高温下折叠外壳蛋白突变体的GroEL/ES突变体。GroEL/ES突变体折叠多种底物蛋白的能力将在体内和体外测定，以获得对这些伴侣蛋白如何识别底物多肽的一般性理解。

DESCRIPTION (provided by applicant): The amino acid sequence of a protein determines its fold. However, small changes such as single amino acid substitutions or deletions can cause misfolding, and subsequent aggregation. Protein misfolding directly causes several devastating human diseases. Molecular chaperones assist the folding of many proteins, especially those prone to misfolding and aggregation. However, how chaperones distinguish between incorrectly and productively folding proteins is unclear. The mechanism of substrate specificity of the major bacterial chaperone complex, GroEL/ES, will be investigated. The major aim of this proposal is to select and characterize mutants of GroEL/ES that more efficiently fold substrate proteins. The coat protein of phage P22 will be the model substrate used to isolate the chaperone mutants because several single amino acid substitutions convert coat protein to become a substrate for GroEL/ES, though with limited efficiency. GroEL/ES mutants will be selected that can fold the coat protein mutants at high temperatures. The ability of the GroEL/ES mutants to fold a variety of substrate proteins will be determined both in vivo and in vitro to gain a generalized understanding of how these chaperone proteins recognize substrate polypeptides.