MODULATING THE REDUCTIVE UNFOLDING PATHWAY OF RNASE A

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。蛋白质的还原展开研究旨在提供有关内切分子的信息。控制自然状态的形成(和稳定)以及折叠/展开路径的相互作用。通过在模型蛋白牛胰腺核糖核酸酶A中将Tyr92突变为G、A或L，并通过Temp.因子和分子动力学模拟这些突变体的晶体结构表明，RNaseA及其结构同源酶显著不同的还原去折叠速率和途径可以归因于牛变异体中Tyr92和Pro93之间的单一、局域、环堆积作用。这种特殊的稳定相互作用在二硫键中的偶然位置。RNaseA的环区导致蛋白质动力学的局部调制，这反过来又增强了二硫键对ReDn的敏感性。导致同系物的还原展开行为的改变。这些结果对白藜芦醇的折叠研究具有重要意义。用于获得折叠/去折叠速率和途径的决定因素，用于通过折叠识别进行蛋白质结构功能预测，以及用于预测蛋白水解性切割位点。在PDB中沉积了三种结构(1YMR、1YMW和1YMN)，并在JACS上发表了这项工作。

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. Reductive unfolding studies of proteins are designed to provide information about intramol. interactions that govern the formation (and stabilization) of the native state and about folding/unfolding pathways. By mutating Tyr92 to G, A, or L in the model protein, bovine pancreatic RNase A, and through analysis of temp. factors and molecular dynamics simulations of the crystal structures of these mutants, it is demonstrated that the markedly different reductive unfolding rates and pathways of RNase A and its structural homolog onconase can be attributed to a single, localized, ring-stacking interaction between Tyr92 and Pro93 in the bovine variant. The fortuitous location of this specific stabilizing interaction in a disulfide-bond-contg. loop region of RNase A results in the localized modulation of protein dynamics that, in turn, enhances the susceptibility of the disulfide bond to redn. leading to an alteration in the reductive unfolding behavior of the homologues. These results have important implications for folding studies involving topol. determinants to obtain folding/unfolding rates and pathways, for protein structure-function prediction through fold recognition, and for predicting proteolytic cleavage sites. Three structures were deposited in the PDB (1YMR, 1YMW, and 1YMN) and the work was published in JACS.