Crystal structures of the pilus retraction motor PilT suggest large domain movements and subunit cooperation drive motility
Crystal structures of the pilus retraction motor PilT suggest large domain movements and subunit cooperation drive motility
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DOI：
10.1016/j.str.2007.01.018
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发表时间：
2007-03-01
期刊：
影响因子：
5.7
通讯作者：
Forest, Katrina T.
中科院分区：
文献类型：
--
作者：
Satyshur, Kenneth A.;Worzalla, Gregory A.;Forest, Katrina T.
PILT是细菌IV型菌毛回缩和表面运动所必需的六聚体ATPase。ADP和ATP结合的Aquifex aeolicus PILT在2.8埃和3.2埃分辨率下的晶体结构显示N端PAS样和C端RecA样ATPase结构域以及一组短的C端螺旋。六聚体是由一个单体的ATPase核心和下一个单体的N-末端结构域之间广泛的极性亚单位相互作用形成的。一个额外的结构捕获了一个不对称的PILT六角体，其中从两个亚基到结合核苷酸的不变精氨酸形成了一个具有酶活性的活性部位。一组PILT突变突出了精氨酸、PAS样结构域、极性亚单位界面和C-末端螺旋对回缩的重要性。我们提出了一个模型，ATP结合导致戏剧性的PILT结构域运动，精氨酸线的接触，以及在这个六聚体马达中的亚单位通信。我们的结论适用于整个II型/IV型分泌物ATPase家族。
PilT is a hexameric ATPase required for bacterial type IV pilus retraction and surface motility. Crystal structures of ADP- and ATP-bound Aquifex aeolicus PilT at 2.8 and 3.2 angstrom resolution show N-terminal PAS-like and C-terminal RecA-like ATPase domains followed by a set of short C-terminal helices. The hexamer is formed by extensive polar subunit interactions between the ATPase core of one monomer and the N-terminal domain of the next. An additional structure captures a nonsymmetric PilT hexamer in which approach of invariant arginines from two subunits to the bound nucleotide forms an enzymatically competent active site. A panel of pilT mutations highlights the importance of the arginines, the PAS-like domain, the polar subunit interface, and the C-terminal helices for retraction. We present a model for ATP binding leading to dramatic PilT domain motions, engagement of the arginine wire, and subunit communication in this hexameric motor. Our conclusions apply to the entire type II/IV secretion ATPase family.