Crystal structure and functional implications of Pyrococcus furiosus hef helicase domain involved in branched DNA processing
Crystal structure and functional implications of Pyrococcus furiosus hef helicase domain involved in branched DNA processing
复制标题
DOI：
10.1016/j.str.2004.11.008
复制
发表时间：
2005-01-01
期刊：
影响因子：
5.7
通讯作者：
Morikawa, K
中科院分区：
文献类型：
--
作者：
Nishino, T;Komori, K;Morikawa, K
DNA和RNA经常形成各种分支中间体，对遗传信息的传递很重要。解旋酶在核酸代谢过程中这些短暂中间体的加工中起着关键作用。古细菌Hef解旋酶/核酸酶是处理皮瓣或叉状dna结构的代表性蛋白质，有趣的是，它的c端一半属于XPF/Mus81核酸酶家族。本文报道了炽热焦球菌Hef蛋白解旋酶结构域的晶体结构。该结构揭示了两个保守解旋酶核心结构域之间的新型螺旋插入。这个带正电的额外区域，结构上类似于DNA聚合酶的“拇指”结构域，在叉子识别中起着关键作用。Hef解旋酶/核酸酶与酿酒酵母的Mph1解旋酶序列相似；XPF/Rad1，参与DNA修复；以及在哺乳动物中发现的假定的Hef同源物。因此，我们的发现为解旋酶/核酸酶家族的功能机制提供了结构基础。
DNA and RNA frequently form various branched intermediates that are important for the transmission of genetic information. Helicases play pivotal roles in the processing of these transient intermediates during nucleic acid metabolism. The archaeal Hef helicase/nuclease is a representative protein that processes flap- or fork-DNA structures, and, intriguingly, its C-terminal half belongs to the XPF/Mus81 nuclease family. Here, we report the crystal structure of the helicase domain of the Hef protein from Pyrococcus furiosus. The structure reveals a novel helical insertion between the two conserved helicase core domains. This positively charged extra region, structurally similar to the "thumb" domain of DNA polymerase, plays critical roles in fork recognition. The Hef helicase/nuclease exhibits sequence similarity to the Mph1 helicase from Saccharomyces cerevisiae; XPF/Rad1, involved in DNA repair; and a putative Hef homolog identified in mammals. Hence, our findings provide a structural basis for the functional mechanisms of this helicase/nuclease family.