Crystal Structure of a Type IV Pilus Assembly ATPase: Insights into the Molecular Mechanism of PilB from Thermus thermophilus
Crystal Structure of a Type IV Pilus Assembly ATPase: Insights into the Molecular Mechanism of PilB from Thermus thermophilus
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DOI：
10.1016/j.str.2016.08.010
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发表时间：
2016-11-01
期刊：
影响因子：
5.7
通讯作者：
Schubot, Florian D.
中科院分区：
文献类型：
--
作者：
Mancl, Jordan M.;Black, Wesley P.;Schubot, Florian D.
IV型皮利（T4 P）介导细菌运动性和毒力。PilB/GspE家族ATP酶为T4 P和2型分泌系统的组装提供动力。我们确定了与ATP γ S复合的PilB（PilB（ATP））的ATP酶区域的结构，以提供T4 P组装ATP酶的模型和以优于3埃的分辨率观察PilB/GspE家族六聚体。原聚体的空间定位和构象表明了力产生的机制。所有六种PilBATP原聚体都含有结合的ATPgS。两个原体形成一个封闭的构象，准备ATP水解。其他四个分子呈现开放构象，但分离成两对不同的活性位点accessories。我们建议，一对代表后水解阶段，而另一对似乎准备ADP/ATP交换。总的来说，数据表明，T4 P组装是通过协调跨PilB六聚体的同时底物结合与ATP水解来提供动力的。
Type IV pili (T4P) mediate bacterial motility and virulence. The PilB/GspE family ATPases power the assembly of T4P and type 2 secretion systems. We determined the structure of the ATPase region of PilB (PilB(ATP)) in complex with ATP gamma S to provide a model of a T4P assembly ATPase and a view of a PilB/GspE family hexamer at better than 3-angstrom resolution. Spatial positioning and conformations of the protomers suggest a mechanism of force generation. All six PilBATP protomers contain bound ATPgS. Two protomers form a closed conformation poised for ATP hydrolysis. The other four molecules assume an open conformation but separate into two pairs with distinct active-site accessibilities. We propose that one pair represents the post-hydrolysis phase while the other pair appears poised for ADP/ATP exchange. Collectively, the data suggest that T4P assembly is powered by coordinating concurrent substrate binding with ATP hydrolysis across the PilB hexamer.