Functional and physical interaction between WRN helicase and human replication protein A
Functional and physical interaction between WRN helicase and human replication protein A
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DOI：
10.1074/jbc.274.26.18341
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发表时间：
1999-06-25
影响因子：
4.8
通讯作者：
Bohr, VA
中科院分区：
文献类型：
--
作者：
Brosh, RM;Orren, DK;Bohr, VA
人类早衰障碍Werner综合征(WS)与正常衰老表现出的大量症状有关。WRN基因产物是一种DNA解旋酶，先前已被证明在单链DNA结合蛋白的刺激下，在反应中解开短DNA双链(小于或等于53个碱基对)。我们研究了纯化的WRN蛋白在各种DNA双链底物上的解旋酶活性，以更详细地表征该酶的解离特性。WRN解旋酶可以催化长达849个碱基对的双链DNA底物的解旋，这一反应依赖于人类复制蛋白A(HrpA)。大肠杆菌SSB和噬菌体T4基因32蛋白(Gp32)完全不能刺激WRN解旋酶解开长的DNA双链，提示WRN与HrpA之间存在特异的功能相互作用。到目前为止，还没有关于WRN解旋酶与其他蛋白质之间的任何物理相互作用的报道。为了支持功能相互作用，我们通过免疫共沉淀纯化的蛋白质证明了WRN和HrpA之间的直接相互作用。WRN和HrpA之间的物理和功能相互作用表明，这两种蛋白在体内可能通过复制、重组或修复等DNA代谢途径共同发挥作用。
The human premature aging disorder Werner syndrome (WS) is associated with a large number of symptoms displayed in normal aging. The WRN gene product, a DNA helicase, has been previously shown to unwind short DNA duplexes (less than or equal to 53 base pairs) in a reaction stimulated by single-stranded DNA-binding proteins. We have studied the helicase activity of purified WRN protein on a variety of DNA duplex substrates to characterize the unwinding properties of the enzyme in greater detail. WRN helicase can catalyze unwinding of long duplex DNA substrates up to 849 base pairs in a reaction dependent on human replication protein A (hRPA). Escherichia coli SSB and bacteriophage T4 gene 32 protein (gp32) completely failed to stimulate WRN helicase to unwind long DNA duplexes indicating a specific functional interaction between WRN and hRPA. So far, there have been no reports of any physical interactions between WRN helicase and other proteins. In support of the functional interaction, we demonstrate a direct interaction between WRN and hRPA by coimmunoprecipitation of purified proteins. The physical and functional interaction between WRN and hRPA suggests that the two proteins may function together in vivo in a pathway of DNA metabolism such as replication, recombination, or repair.