ATPase site architecture and helicase mechanism of an archaeal MCM
ATPase site architecture and helicase mechanism of an archaeal MCM
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DOI：
10.1016/j.molcel.2007.08.013
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发表时间：
2007-10-26
期刊：
影响因子：
16
通讯作者：
Bell, Stephen D.
中科院分区：
文献类型：
--
作者：
Moreau, MaIllew J.;McGeoch, Adam T.;Bell, Stephen D.
MCM复合物是古生菌和真核生物的假定复制解旋酶的亚基，是ATP酶AAA+（与各种细胞活性相关的ATP酶）家族的成员。这个家族中的蛋白质利用ATP水解的化学能来执行广泛的细胞过程。在这里，我们调查的AAA+网站中的小型染色体维护（MCM）复杂的古菌硫磺硫化叶菌（SsoMCM）的功能。我们发现，SsoMCM有一个不寻常的活性位点的架构，具有独特的混合功能，以前只发现在不同的家庭的AAA+蛋白质。我们还描述了一系列的突变体掺杂实验，以调查解旋酶活性产生的亚基间协调的机制基础。我们的研究结果表明，MCM可以容忍催化失活的亚基，仍然作为解旋酶的功能，使我们提出了一个半连续模型解旋酶活性的这种复杂的。
The subunits of the presumptive replicative helicase of archaea and eukaryotes, the MCM complex, are members of the AAA+ (ATPase-associated with various cellular activities) family of ATPases. Proteins within this family harness the chemical energy of ATP hydrolysis to perform a broad range of cellular processes. Here, we investigate the function of the AAA+ site in the mini-chromosome maintenance (MCM) complex of the archaeon Sulfolobus solfataricus (SsoMCM). We find that SsoMCM has an unusual active-site architecture, with a unique blend of features previously found only in distinct families of AAA+ proteins. We additionally describe a series of mutant doping experiments to investigate the mechanistic basis of inter-subunit coordination in the generation of helicase activity. Our results indicate that MCM can tolerate catalytically inactive subunits and still function as a helicase, leading us to propose a semisequential model for helicase activity of this complex.