The archaeal Hjm helicase has recQ-like functions, and may be involved in repair of stalled replication fork
The archaeal Hjm helicase has recQ-like functions, and may be involved in repair of stalled replication fork
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DOI：
10.1111/j.1365-2443.2006.00925.x
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发表时间：
2006-02-01
期刊：
影响因子：
2.1
通讯作者：
Ishino, Y
中科院分区：
文献类型：
--
作者：
Fujikane, R;Shinagawa, H;Ishino, Y
古细菌Hjm是一种结构特异性DNA解旋酶，最初通过体外筛选Holliday连接迁移活性在极端嗜热古细菌Pyrococcus furiosus中鉴定。进一步的生化分析表明，来自P.furiosus的Hjm蛋白在体外与叉相关的Y结构DNA结合，并解旋它们的双链区域，就像E. coli RecQ蛋白。此外，遗传分析表明，Hjm产生于E。coli细胞部分弥补了recQ突变体E.大肠杆菌菌株。这些结果表明，Hjm可能是一个功能性的RecQ在Escherichia，在其中它是必要的基因组的完整性的维护，虽然氨基酸序列是不保守的。Hjm与PCNA的解旋酶活性的功能性相互作用进一步表明Hjm在停滞的复制叉处起作用，作为重建的复制体的成员重新开始复制。
The archaeal Hjm is a structure-specific DNA helicase, which was originally identified in the hyperthermophilic archaeon, Pyrococcus furiosus, by in vitro screening for Holliday junction migration activity. Further biochemical analyses of the Hjm protein from P. furiosus showed that this protein preferably binds to fork-related Y-structured DNAs and unwinds their double-stranded regions in vitro, just like the E. coli RecQ protein. Furthermore, genetic analyses showed that Hjm produced in E. coli cells partially complemented the defect of functions of RecQ in a recQ mutant E. coli strain. These results suggest that Hjm may be a functional counterpart of RecQ in Archaea, in which it is necessary for the maintenance of genome integrity, although the amino acid sequences are not conserved. The functional interaction of Hjm with PCNA for its helicase activity further suggests that the Hjm works at stalled replication forks, as a member of the reconstituted replisomes to restart replication.