BACTERIAL CHAPERONIN MACHINES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。伴侣蛋白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双环复合物，而它的共伴侣蛋白GroES是一个大小为70-kDa的7-meric单环复合物。分子伴侣促进适当折叠的机制引起了极大的兴趣。然而，大多数研究使用小蛋白或合成肽作为模型底物。有限的信息是可用的这些伴侣如何介导折叠和/或组装异质寡聚蛋白或大分子结构。为了了解伴侣蛋白辅助蛋白折叠和组装的机制，我们计划开展以下低温电镜研究。具体目标：1；继续使用GroEL双环配合物作为低温电镜重建的模型，目标是达到4-¿分辨率。2. 确定与亚基结合的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