Characterization of Werner syndrome protein DNA helicase activity: directionality, substrate dependence and stimulation by replication protein A
Characterization of Werner syndrome protein DNA helicase activity: directionality, substrate dependence and stimulation by replication protein A
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DOI：
10.1093/nar/26.12.2879
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发表时间：
1998-06-15
影响因子：
14.9
通讯作者：
Loeb, LA
中科院分区：
文献类型：
--
作者：
Shen, JC;Gray, MD;Loeb, LA
沃纳综合征是一种遗传性疾病，其特征是过早衰老、遗传不稳定和癌症高发。野生型Werner综合征蛋白（WRN）已被证明在体外表现出DNA解旋酶活性。本文报道了WRN解旋酶的进一步生物化学特性。该酶解螺旋双链DNA，在酶结合链上转位3 '->5'，水解dATP或ATP，并在较小程度上水解dCTP或CTP，支持WRN催化的链置换，ATP和dATP的Km值分别为51和119 μ M，CTP和dCTP的Km值分别为2.1和3.9 mM，在大肠杆菌、T4噬菌体和人的单链DNA结合蛋白中，人单链DNA结合蛋白对WRN的链置换活性有促进作用，（人复制蛋白A，hRPA）是最广泛的并且以表明与WRN直接相互作用的化学计量发生，WRN与hRPA相互作用的缺陷可能与Werner综合征细胞中发生频率升高的缺失突变有关。
Werner syndrome is an inherited disease characterized by premature aging, genetic instability and a high incidence of cancer. The wild type Werner syndrome protein (WRN) has been demonstrated to exhibit DNA helicase activity in vitro. Here we report further biochemical characterization of the WRN helicase, The enzyme unwinds double-stranded DNA, translocating 3'-->5' on the enzyme-bound strand, Hydrolysis of dATP or ATP, and to a lesser extent hydrolysis of dCTP or CTP, supports WRN-catalyzed strand-displacement, K-m values for ATP and dATP are 51 and 119 mu M, respectively, and 2.1 and 3.9 mM for CTP and dCTP, respectively, Strand-displacement activity of WRN is stimulated by single-stranded DNA-binding proteins (SSBs), Among the SSBs from Escherichia coli, bacteriophage T4 and human, stimulation by human SSB (human replication protein A, hRPA) is the most extensive and occurs with a stoichiometry which suggests direct interaction with WRN, A deficit in the interaction of WRN with hRPA may be associated with deletion mutations that occur at elevated frequency in Werner syndrome cells.