HsDmc1蛋白（RecA蛋白的减数分裂人类同源物）的重组活性。
Recombination activities of HsDmc1 protein, the meiotic human homolog of RecA protein.
作者信息
Li Z, Golub E I, Gupta R, Radding C M
机构信息
Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
出版信息
Proc Natl Acad Sci U S A. 1997 Oct 14;94(21):11221-6. doi: 10.1073/pnas.94.21.11221.
Meiosis-specific homologs of RecA protein have been identified in Saccharomyces cerevisiae and higher eukaryotes including mammals, but their enzymatic activities have not been described. We have purified the human protein HsDmc1 produced in Escherichia coli from a cloned copy of the cDNA. The recombinant enzyme had DNA-dependent ATPase activity with an estimated kcat of 1.5 min-1. DNase protection experiments with oligonucleotides as substrates indicated that HsDmc1 protein binds preferentially to single-stranded DNA with a stoichiometry of approximately one molecule of protein per three nucleotide residues. HsDmc1 protein catalyzed the formation of D-loops in superhelical DNA, as well as strand exchange between single-stranded and double-stranded oligonucleotides. The requirements for strand exchange catalyzed by HsDmc1 were similar to those of RecA protein, but exchange caused by HsDmc1 was not supported by ATPgammaS.
在酿酒酵母以及包括哺乳动物在内的高等真核生物中，已鉴定出RecA蛋白的减数分裂特异性同源物，但尚未对其酶活性进行描述。我们从cDNA的克隆拷贝中纯化了在大肠杆菌中产生的人类蛋白HsDmc1。该重组酶具有依赖于DNA的ATP酶活性，估计催化常数（kcat）为1.5分钟⁻¹。以寡核苷酸为底物的DNase保护实验表明，HsDmc1蛋白优先结合单链DNA，化学计量比约为每三个核苷酸残基一个蛋白分子。HsDmc1蛋白催化超螺旋DNA中D环的形成，以及单链和双链寡核苷酸之间的链交换。HsDmc1催化链交换的条件与RecA蛋白相似，但ATPγS不支持HsDmc1引起的交换。
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