Life of proteins: maturation, translocation, quality control in the cell

蛋白质的生命：细胞内的成熟、易位、质量控制

基本信息

批准号：
14037217
负责人：
YOSHIDA Masasuke
金额：
$ 104.32万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14037217/
关键词：
GroEL Prion Sup35 ClpB FtsH Hsp104 DnaK chaperone 分子シャペロンシャペロニンプリオン脱凝集

项目摘要

We found an intermediate of GroEL-GroES-assisted protein folding in which substrate protein is tethered to the GroEL's binding sites sharing with GroES. Substrate protein cannot initiate folding in this intermediate until it is release into the cis-cavity. The crystal structure of GroEL-GroES complex with the substrate protein being in cis-cavity. The GroEL ring is deviated from the heptamer symmetry. It was thought that ADP can support chaperonin function but we re-confirmed that only ATP can support folding when ADP was extensively removed from ATP solution.Sup35, an yeast prion protein, forms a prion fiber. We found Hsp 104 and unkown factor contained in the yeast lysate can break the prion fibers. It is ATP dependent. X-ray diffraction of the prion fibers ondicates that beta helix, rather than widely-believed cross-beta, is a plasusible structure of the fiber.ClpB is a chaperon that can disaggregate the heat-denatured proteins in an ATP dependent manner with cooperation with DnaK system. We succeeded in crystal structure analysis of ClpB from thermophilic bacteria. A long alfa-helix beside the two nucleotide binding domains features the structure and mechanistic model of disaggregation was proposed. We also determined crystal structures of ATP-dependent protease, FtsH. Protease domain has hexamer symmetry but ATP-binding domains have three fold symmetry. There is a narrow path to reach protease active site from the outside and ATP-driven open-closed motion seems to provide polypeptide pulling reaction.

我们发现了 GroEL-GroES 辅助蛋白质折叠的中间体，其中底物蛋白质被束缚在与 GroES 共享的 GroEL 结合位点上。底物蛋白不能在该中间体中开始折叠，直到它被释放到顺式腔中。 GroEL-GroES 复合物的晶体结构，底物蛋白处于顺式空腔中。 GroEL 环偏离七聚体对称性。人们认为ADP可以支持伴侣蛋白功能，但我们再次确认，当ADP从ATP溶液中大量去除时，只有ATP可以支持折叠。Sup35，一种酵母朊病毒蛋白，形成朊病毒纤维。我们发现酵母裂解物中含有的Hsp 104和未知因子可以破坏朊病毒纤维。它依赖于 ATP。朊病毒纤维的 X 射线衍射表明，β 螺旋，而不是广泛认为的交叉β，是纤维的合理结构。ClpB 是一种伴侣，可以与 ATP 依赖的方式解聚热变性蛋白质DnaK 系统。我们成功地分析了嗜热细菌 ClpB 的晶体结构。提出了两个核苷酸结合域旁边的长α螺旋的结构和解聚机制模型。我们还确定了 ATP 依赖性蛋白酶 FtsH 的晶体结构。蛋白酶结构域具有六聚体对称性，但 ATP 结合结构域具有三重对称性。从外部到达蛋白酶活性位点的路径很窄，并且 ATP 驱动的开闭运动似乎提供了多肽牵引反应。