GENERAL MECHANISM FOR RECA PROTEIN-BINDING TO DUPLEX DNA
GENERAL MECHANISM FOR RECA PROTEIN-BINDING TO DUPLEX DNA
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DOI：
10.1016/0022-2836(88)90014-9
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发表时间：
1988-09-20
影响因子：
5.6
通讯作者：
COX, MM
中科院分区：
文献类型：
--
作者：
PUGH, BF;COX, MM
RecA蛋白与双链DNA的结合是一个多步骤的过程。Tau分析最初是为了检测RNA聚合酶与启动子DNA的结合，在这里被用来更详细地研究RecA-双链(DS)DNA复合体形成的两个动力学上可区分的反应片段。一种可能是RecA蛋白与天然dsDNA弱结合的快速预平衡，它被发现具有以下性质：(1)对pH的敏感性，涉及大约一个质子的净释放；(2)对盐的敏感性；(3)很少或不依赖于温度；(4)很少或不依赖于DNA长度。第二个反应环节，核蛋白细丝形成的限速成核伴随着部分DNA解旋，被发现具有以下性质：(1)对pH的敏感性，涉及大约3个质子的净吸收；(2)对盐的敏感性；(3)对温度的相对较大的依赖性，阿累尼乌斯活化能为39kcal mol-1；(4)对DNA拓扑的敏感性；(5)对DNA长度的依赖性。这些结果有助于RecA蛋白与双链DNA结合的一般机制，这可以为明显的优先结合到改变的DNA结构，如嘧啶二聚体和Z-DNA提供理论基础。
RecA protein binding to duplex DNA occurs by a multi-step process. The tau analysis, originally developed to examine the binding of RNA polymerase to promoter DNA, is adapted here to study two kinetically distinguishable reaction segments of RecA-double stranded (ds) DNA complex formation in greater detail. One, which is probably a rapid pre-equilibrium in which RecA protein binds weakly to native dsDNA, is found to have the following properties: (1) a sensitivity to pH, involving a net release of approximately one proton; (2) a sensitivity to salts; (3) little or no dependence on temperature; (4) little or no dependence on DNA length. The second reaction segment, the rate-limiting nucleation of nucleoprotein filament formation accompanied by partial DNA unwinding, is found to have the following properties: (1) a sensitivity to pH, involving a net uptake of approximately three protons; (2) a sensitivity to salts; (3) a relatively large dependence on temperature, with an Arrhenius activation energy of 39 kcal mol-1; (4) a sensitivity to DNA topology; (5) a dependence on DNA length. These results contribute to a general mechanism for RecA protein binding to duplex DNA, which can provide a rationale for the apparent preferential binding to altered DNA structures such as pyrimidine dimers and Z-DNA.