STRUCTURE AND FUNCTION OF THE CLPXP ATP-DEPENDENT PROTEASE

CLPXP ATP 依赖性蛋白酶的结构和功能

• 批准号: 7369492
• 负责人: TANIA A BAKER
• 金额: $ 0.07万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7369492
• 关键词: STRUCTURE; FUNCTION; CLPXP; ATP; DEPENDENT

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. We had previously solved the structure of the AAA+ adaptor protein SspB in complex with one of its substrates, the ssrA tag. In E. coli, this tag targets incompletely synthesized proteins from stalled ribosomes for destruction by the ClpXP degradation machine, a process that is accelerated by SspB. Biochemical studies have revealed that other substrates are targeted to ClpXP by SspB, including the n-terminal fragment of RseA. RseA is a trans-membrane protein that functions as a master regulator of the extra-cytoplasmic stress response in E. coli. Targeting of n-terminal fragment for degradation by ClpXP is required for the release of the sigma factor (sigma E) and activation stress response genes. Using biochemical and biophysical techniques, a 31 amino acid stretch of the RseA sequence was identified as the SspB-binding determinant. In order to understand the structural basis for the SspB-RseA interaction, we crystallized the protein in complex with this 31 amino acid peptide. Energy-dependent proteases often rely on adaptor proteins to modulate substrate recognition. The SspB adaptor binds peptide sequences in the stress-response regulator RseA and in ssrA-tagged proteins and delivers these molecules to the AAA+ ClpXP protease for degradation. The structure of SspB bound to an ssrA peptide is known. Here, we reported the crystal structure of a complex between SspB and its recognition peptide in RseA in Nat. Struct. Mol. Biol. Notably, the RseA sequence is positioned in the peptide-binding groove of SspB in a direction opposite to the ssrA peptide, the two peptides share only one common interaction with the adaptor, and the RseA interaction site is substantially larger than the overlapping ssrA site. This marked diversity in SspB recognition of different target proteins indicates that it is capable of highly flexible and dynamic substrate delivery

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子弹和调查员（PI）可能已经从其他NIH来源获得了主要资金，因此可以在其他清晰的条目中代表。列出的机构适用于该中心，这不一定是调查员的机构。我们以前曾与其一种底物SSRA标签之一求解了AAA+衔接蛋白SSPB的结构。在大肠杆菌中，此标签靶向不完全合成的蛋白质来自停滞的核糖体，以破坏CLPXP降解机，这一过程由SSPB加速。生化研究表明，其他底物针对SSPB（包括RSEA的N末端片段）靶向CLPXP。 RSEA是一种跨膜蛋白，可作为大肠杆菌中胞质应激反应的主要调节剂。释放Sigma因子（Sigma E）和激活应力响应基因需要将N末端片段靶向降解。使用生化和生物物理技术，RSEA序列的31个氨基酸伸展被确定为SSPB结合决定因素。为了了解SSPB-RSEA相互作用的结构基础，我们将蛋白质与该31个氨基酸肽复合体结晶。能量依赖性蛋白酶通常依靠衔接蛋白来调节底物识别。 SSPB适配器在应力响应调节剂RSEA和SSRA标记的蛋白中结合肽序列，并将这些分子传递到AAA+ CLPXP蛋白酶以降解。已知与SSSRA肽结合的SSPB的结构已知。在这里，我们报道了SSPB及其识别肽在NAT中的RSEA中的晶体结构。结构。摩尔。生物。值得注意的是，RSEA序列位于SSPB的肽结合凹槽中，沿与SSRA肽相反的方向，两种肽与适配器仅具有一个共同的相互作用，而RSEA相互作用位点基本上大于重叠的SSRA位点。 SSPB识别不同靶蛋白的这种明显的多样性表明它能够高度柔韧和动态的底物递送