Pseudomonas aeruginosa C-Terminal Processing Protease CtpA Assembles into a Hexameric Structure That Requires Activation by a Spiral-Shaped Lipoprotein-Binding Partner.
Pseudomonas aeruginosa C-Terminal Processing Protease CtpA Assembles into a Hexameric Structure That Requires Activation by a Spiral-Shaped Lipoprotein-Binding Partner.
复制标题
铜绿假单胞菌C-末端加工蛋白酶CtpA组装成六聚体结构，需要由螺旋形脂蛋白结合伴侣激活。
作者：
Hsu HC;Wang M;Kovach A;Darwin AJ;Li H
铜绿假单胞菌CtpA是一种羧基末端加工蛋白酶，与外膜脂蛋白LbcA合作降解至少五种细胞壁相关蛋白，其中四种是细胞壁水解酶。这种活性在急性肺炎小鼠模型中支持铜绿假单胞菌毒力方面起着重要作用。然而，对CtpA和LbcA功能的分子机制几乎一无所知。在这里，我们使用的结构分析表明，CtpA单独组装成一个无活性的六聚体，包括一个三聚体的二聚体，这限制了其基板的访问，并防止非特异性降解。衔接蛋白LbcA是一个右旋开放螺旋，具有11个三肽重复序列，可以包裹底物，将其传递给CtpA进行降解。通过结构导向突变和功能测定，我们还表明，CtpA的二聚体和LbcA的N-末端螺旋的三聚体的接口是重要的LbcA介导的底物降解CtpA在体外和体内。这项工作提高了我们对LbcA-CtpA蛋白水解系统的分子机制的理解，并揭示了与其他一些细菌CTP中发现的排列的一些显着差异。
Pseudomonas aeruginosa CtpA is a carboxyl-terminal processing protease that partners with the outer membrane lipoprotein LbcA to degrade at least five cell wall-associated proteins, four of which are cell wall hydrolases. This activity plays an important role in supporting P. aeruginosa virulence in a mouse model of acute pneumonia. However, almost nothing is known about the molecular mechanisms underlying CtpA and LbcA function. Here, we used structural analysis to show that CtpA alone assembles into an inactive hexamer comprising a trimer of dimers, which limits its substrate access and prevents nonspecific degradation. The adaptor protein LbcA is a right-handed open spiral with 11 tetratricopeptide repeats, which might wrap around a substrate to deliver it to CtpA for degradation. By structure-guided mutagenesis and functional assays, we also showed that the interfaces of the CtpA trimer of dimers and an N-terminal helix of LbcA are important for LbcA-mediated substrate degradation by CtpA both in vitro and in vivo. This work improves our understanding of the molecular mechanism of the LbcA-CtpA proteolytic system and reveals some striking differences from the arrangements found in some other bacterial CTPs.
登录
查看更多内容
影响因子：
5.2
作者：
Park SH;Kim YJ;Lee HB;Seok YJ;Lee CR
通讯作者：
Lee CR
影响因子：
3.2
作者：
Chung, Sammi;Darwin, Andrew J.
通讯作者：
Darwin, Andrew J.
影响因子：
2.1
作者：
Hoge, Rien;Laschinski, Marko;Rosenau, Frank
通讯作者：
Rosenau, Frank
影响因子：
14.9
作者：
Ntountoumi, Chrysa;Vlastaridis, Panayotis;Amoutzias, Grigoris D.
通讯作者：
Amoutzias, Grigoris D.
影响因子：
2.8
作者：
Carroll, Ronan K.;Rivera, Frances E.;Shaw, Lindsey N.
通讯作者：
Shaw, Lindsey N.