SUBUNIT ORGANIZATION AND STRUCTURE OF LON PROTEASE

LON蛋白酶的亚基组织和结构

• 批准号: 6290705
• 负责人: Richard D Leapman
• 金额: --
• 依托单位: OFFICE OF THE DIRECTOR, NATIONAL INSTITUTES OF HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6290705
• 关键词: enzyme structure; enzyme substrate; molecular weight; protein sequence; scanning transmission electron microscopy; serine proteinases; structural biology

Scanning transmission electron microscopy (STEM) has been applied to determine the subunit organization of the ATP-dependent protease, Lon. This enzyme plays an important role in degrading misfolded proteins in prokaryotes as well as in the mitochrondria of eukaryotes. Lon consists of multiple copies of a single polypeptide chain that contains both the ATPase (A) and protease (P) domains. The sequence of bacterial Lon has a strong homology with eukaryotic Lon which has been reported to form heptameric rings. However, for bacterial Lon, currently published data are inconclusive. Dark-field STEM measurements show that full-length E. coli Lon (wild type and a ser-ala mutant) as well as Lon-NA are composed of dodecamers, whereas Lon-AP forms hexamers. By analogy with the protein ClpA which is the ATPase component of the ClpAP protease complex, it is likely that Lon is comprised of two hexameric rings. The fact that Lon-AP only forms hexamers suggests that the N-terminal domain may be required for association of two hexameric rings in the holoenzyme. - Scanning transmission electron microscopy, lon protease, subunit organization, structure, molecular weight

已应用扫描透射电子显微镜（Stem）来确定ATP依赖性蛋白酶LON的亚基组织。这种酶在降解原核生物以及真核生物线虫中的错误折叠蛋白方面起着重要作用。 LON由单个多肽链的多个副本组成，该副链既包含ATPase（A）和蛋白酶（P）域。细菌LON的序列与真核LON具有很强的同源性，据报道形成七聚环。但是，对于细菌LON，目前已发布的数据尚无定论。暗场茎的测量表明，全长的大肠杆菌lon（野生型和ser-ala突变体）以及伦纳（Lon-Na）由十二焦点组成，而lon-ap形成了六聚体。通过类似于蛋白质CLPA，该蛋白CLPA是CLPAP蛋白酶复合物的ATPase成分，LON可能由两个六聚体环组成。伦普仅形成六聚体的事实表明，全酶中两个六聚体环的关联可能需要N末端结构域。 - 扫描透射电子显微镜，LON蛋白酶，亚基组织，结构，分子量