Structure and mechanism of the RuvB Holliday junction branch migration motor
Structure and mechanism of the RuvB Holliday junction branch migration motor
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DOI：
10.1006/jmbi.2001.4852
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发表时间：
2001-08-10
影响因子：
5.6
通讯作者：
Tainer, JA
中科院分区：
文献类型：
--
作者：
Putnam, CD;Clancy, SB;Tainer, JA
RuvB六角体是RuvAB复合体的化学机械马达，在DNA重组和挽救停滞不前的DNA复制叉时迁移Holliday连接分支点。该基因的1.6埃晶体结构和5个突变结构表明，RuvB是一种与多种细胞活性相关的ATPase(AAA+类ATPase)，其DNA结合域为带翼的螺旋。RuvB-ADP复合体的结构和突变揭示了AAA+类ATPase是如何将核苷酸结合和水解作用结合到结构域之间的构象。晶体堆积和溶液中的小角X射线散射所暗示的RuVB六角体内部的变化和不对称性。ATP驱动的结构域运动定位于通过六角体移动双链DNA，并通过改变互补的亲水性蛋白质-蛋白质界面来驱动亚基之间的构象变化。对蛋白质中五个基序的结构和生化分析表明，ATP结合是传感器和Walker基序都能识别的应变构象，亚基间的激活是通过精氨酸手指基序进行的，这使人想起GTPase激活蛋白。综上所述，这些结果为RuvB如何作为Holliday连接的分支迁移的发动机提供了见解。(C)2001年学术出版社。
The RuvB hexamer is the chemomechanical motor of the RuvAB complex that migrates Holliday junction branch-points in DNA recombination and the rescue of stalled DNA replication forks. The 1.6 Angstrom crystal structure of Thermotoga maritima RuvB together with five mutant structures reveal that RuvB is an ATPase-associated with diverse cellular activities (AAA + -class ATPase) with a winged-helix DNA-binding domain. The RuvB-ADP complex structure and mutagenesis suggest how AAA + class ATPases couple nucleotide binding and hydrolysis to interdomain conformational. changes and asymmetry within the RuvB hexamer implied by the crystallographic packing and small-angle X-ray scattering in solution. ATP-driven domain motion is positioned to move double-stranded DNA through the hexamer and drive conformational changes between subunits by altering the complementary hydrophilic protein-protein interfaces. Structural and biochemical analysis of five motifs in the protein suggest that ATP binding is a strained conformation recognized both by sensors and the Walker motifs and that intersubunit activation occurs by an arginine finger motif reminiscent of the GTPase-activating proteins. Taken together, these results provide insights into how RuvB functions as a motor for branch migration of Holliday junctions. (C) 2001 Academic Press.