CRYSTAL STRUCTURES OF SECA AND SECT-SECYEG COMPLEXES

SECA 和 SECT-SECYEG 复合物的晶体结构

• 批准号: 7955103
• 负责人: Tom A Rapoport
• 金额: $ 6.64万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7955103
• 关键词: ATP phosphohydrolase; Archaea; Bacteria; Binding; Cell membrane; Complex; Computer Retrieval of Information on Scientific Projects Database; Data; Funding; Grant; Institution; Membrane Proteins; Research; Research Personnel; Resources; Role; Source; Structure; Thermotoga maritima; United States National Institutes of Health; dimer; interest; monomer; polypeptide; protein complex; protein transport; structural biology

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. 1. Many proteins are transported after their synthesis across the bacterial plasma membrane. They are moved by the SecA ATPase through a translocation channel that is formed by a heterotrimeric membrane protein complex, called the SecYEG complex. Structures of the SecA ATPase had been determined before and a structure of the channel from an archaebacterium had also been determined. The next step was therefore to determine the structure of the SecA ATPase bound to the channel. 2. SecA is the ATPase that is responsible for the post-translational translocation of polypeptides across the SecY channel in bacteria. Several SecA structures have been determined, but a full understanding of the function of the ATPase has not yet been achieved. One major question concerns the role of a SecA dimer. We had obtained data that suggested that SecA functions as a monomer, while others have claimed that it functions as a dimer. In addition to resolving this issue, we became interested in the structure of Thermotoga maritima SecA because we had crystallized the SecA from this species in complex with the channel (see above). The question was whether T. maritima SecA undergoes conformational changes upon binding to the channel.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 1.许多蛋白质在合成后被转运穿过细菌质膜。它们被SecA ATP酶移动通过由异源三聚体膜蛋白复合物（称为SecYEG复合物）形成的易位通道。SecA ATP酶的结构之前已经确定，并且来自古细菌的通道结构也已经确定。因此，下一步是确定与通道结合的SecA ATP酶的结构。 2. SecA是ATP酶，其负责细菌中多肽穿过SecY通道的翻译后易位。已经确定了几种SecA结构，但尚未完全了解ATP酶的功能。一个主要问题涉及SecA二聚体的作用。我们已经获得的数据表明SecA作为单体发挥作用，而其他人则声称它作为二聚体发挥作用。除了解决这个问题，我们对Thermotoga maritima SecA的结构产生了兴趣，因为我们已经从这个物种中结晶出了SecA与通道的复合物（见上文）。问题是T. maritima SecA在与通道结合时经历构象变化。