BACTERIAL CHAPERONIN MACHINES

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。伴侣蛋白的功能是通过与新生或未折叠的多肽相互作用来防止错误折叠，否则会导致聚集。细菌伴侣蛋白GroEL/GroES分别是线粒体Hsp60/Hsp10的同源物。GroEL是一个大小为800 kDa的14-Meric双环复合体，而它的辅助伴侣Groes是一个70 kDa的7-Meric单环复合体。分子伴侣促进适当折叠的机制引起了人们的浓厚兴趣。然而，大多数研究都使用小蛋白或合成多肽作为模型底物。关于这些伴侣如何调节异寡聚蛋白质或大分子结构的折叠和/或组装，现有的信息有限。为了了解伴侣蛋白辅助蛋白质折叠和组装的机制，我们计划进行以下冷冻-EM研究。具体目标：1.继续使用GroEL双环复合体作为冷冻-EM重建的模型，目标是达到4？分辨率。2.确定与subs结合的GroEL单环突变体的三维结构

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. Chaperonins function by interacting with nascent or unfolded polypeptides to prevent misfolding, which otherwise leads to aggregation. Bacterial chaperonins GroEL/GroES are homologues of mitochondrial Hsp60/Hsp10, respectively. GroEL is a 14-meric double-ring complex of 800 kDa in size, whereas its co-chaperonin GroES is a 70-kDa 7-meric single-ring complex. The mechanism by which molecular chaperones promote proper folding is of intense interest. However, most studies have used small proteins or synthetic peptides as model substrates. Limited information is available as to how these chaperones mediate folding and/or assembly of hetero-oligomeric proteins or macromolecular structures. To understand the mechanism underlying chaperonin-assisted protein folding and assembly, we plan to dp the following cryo-EM studies. Specific Aims: 1. To continue using the GroEL double-ring complex as a model for cryo-EM reconstruction with the goal of attaining 4-¿ resolution. 2. To determine three-dimensional structures of single ring mutant of GroEL bound with subs