P. aeruginosa PilT Structures with and without Nucleotide Reveal a Dynamic Type IV Pilus Retraction Motor
P. aeruginosa PilT Structures with and without Nucleotide Reveal a Dynamic Type IV Pilus Retraction Motor
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DOI：
10.1016/j.jmb.2010.05.066
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发表时间：
2010-07-30
影响因子：
5.6
通讯作者：
Forest, Katrina T.
中科院分区：
文献类型：
--
作者：
Misic, Ana M.;Satyshur, Kenneth A.;Forest, Katrina T.
电视型菌毛是细菌的胞外细丝，可以收缩以产生力量和运动。回缩是由马达蛋白PILT完成的。分别在2.6埃和3.1埃分辨率下计算了含和不含结合β，γ-亚甲基腺苷-5‘-三磷酸的铜绿假单胞菌药丸的晶体结构，揭示了由结晶学上的2重对称算符作用于不对称单元中的三个亚基形成的连锁六角体，并通过广泛的离子相互作用保持在一起。两个不变的羧酸盐，Asp Box基序Glu163和Walker B基序Glu204，分别被分配给镁离子结合和催化作用。Gamma-methyleneadenosine-5‘-triphosphate-bound PILT不对称单元中每个亚基中的核苷酸配体排列不均匀。类似地，两种结构不对称单元中的三个亚基表现出两个结构域的不同相对构象。12度和20度的结构域旋转表示在将菌毛分解为膜定位的菌毛单体的ATP偶联机制中发生的运动。结合这些观察结果，我们提出了PILT作用的三态“就绪、主动、释放”模型。(C)2010爱思唯尔有限公司保留所有权利。
Type TV pili are bacterial extracellular filaments that can be retracted to create force and motility. Retraction is accomplished by the motor protein PilT. Crystal structures of Pseudomonas aeruginosa Pill with and without bound beta,gamma-methyleneadenosine-5'-triphosphate have been solved at 2.6 angstrom and 3.1 angstrom resolution, respectively, revealing an interlocking hexamer formed by the action of a crystallographic 2-fold symmetry operator on three subunits in the asymmetric unit and held together by extensive ionic interactions. The roles of two invariant carboxylates, Asp Box motif Glu163 and Walker B motif Glu204, have been assigned to Mg2+ binding and catalysis, respectively. The nucleotide ligands in each of the subunits in the asymmetric unit of the beta,gamma-methyleneadenosine-5'-triphosphate-bound PilT are not equally well ordered Similarly, the three subunits in the asymmetric unit of both structures exhibit differing relative conformations of the two domains. The 12 degrees and 20 degrees domain rotations indicate motions that occur during the ATP-coupled mechanism of the disassembly of pili into membrane-localized pilin monomers. Integrating these observations, we propose a three-state "Ready, Active, Release" model for the action of PilT. (C) 2010 Elsevier Ltd All rights reserved.