The human Rad51 protein: polarity of strand transfer and stimulation by hRP-A
The human Rad51 protein: polarity of strand transfer and stimulation by hRP-A
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DOI：
10.1093/emboj/16.17.5198
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发表时间：
1997-09-01
期刊：
影响因子：
11.4
通讯作者：
West, SC
中科院分区：
文献类型：
--
作者：
Baumann, P;West, SC
人Rad 51蛋白与大肠杆菌RecA蛋白同源，并在体外催化同源配对和链转移反应。使用单链环状和同源线性双链体DNA，我们表明hRad 51通过将线性双链体互补链的5'端转移到ssDNA形成稳定的接合分子。因此，链转移的极性是3'到5'，相对于hRad 51在其上启动丝形成的ssDNA定义。这种极性与用RecA观察到的极性相反。同源配对和链转移需要化学计量的hRad 51，对应于ssDNA的每三个核苷酸一个hRad 51单体。当蛋白质以有限或过量的量存在时，观察不到关节分子。人ssDNA结合蛋白hRP-A刺激hRad 51介导的反应。其作用与从ssDNA中去除二级结构的作用一致，从而促进连续Rad 51细丝的形成。
The human Rad51 protein is homologous to the Escherichia coli RecA protein and catalyses homologous pairing and strand transfer reactions in vitro. Using single-stranded circular and homologous linear duplex DNA, we show that hRad51 forms stable joint molecules by transfer of the 5' end of the complementary strand of the linear duplex to the ssDNA. The polarity of strand transfer is therefore 3' to 5', defined relative to the ssDNA on which hRad51 initiates filament formation. This polarity is opposite to that observed with RecA. Homologous pairing and strand transfer require stoichiometric amounts of hRad51, corresponding to one hRad51 monomer per three nucleotides of ssDNA. Joint molecules are not observed when the protein is present in limiting or excessive amounts. The human ssDNA binding-protein, hRP-A, stimulates hRad51-mediated reactions. Its effect is consistent with a role in the removal of secondary structures from ssDNA, thereby facilitating the formation of continuous Rad51 filaments.