Recombination activities of HsDmc1 protein, the meiotic human homolog of RecA protein.
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.
Li
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Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
Golub
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Gupta
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Radding
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D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D004265:DNA Helicases; D004277:DNA, Single-Stranded / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003850:Deoxyribonuclease I; D004926:Escherichia coli; D006801:Humans; D008540:Meiosis; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D011938:Rec A Recombinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D018797:Cell Cycle Proteins; C513033:DMC1 protein, S cerevisiae; D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D011938:Rec A Recombinases; D003850:Deoxyribonuclease I; D000251:Adenosine Triphosphatases; C074556:DMC1 protein, human; D004265:DNA Helicases