Open AccessStrand exchange activity of human recombination protein Rad52
Author(s) -
Jaspal Kaur Kumar,
Ravindra C. Gupta
Publication year - 2004
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0403416101
Subject(s) - rad52 , d loop , replication protein a , homologous recombination , recombinase , dna , dna repair , biology , microbiology and biotechnology , flp frt recombination , recombination , rad51 , dna supercoil , oligonucleotide , chemistry , biochemistry , dna replication , genetic recombination , dna binding protein , gene , mitochondrial dna , transcription factor
Repair of double-strand breaks is essential for the maintenance of genome integrity and cell survival. In eukaryotes, double-strand-break repair by homologous recombination requires the Rad52 group of proteins. Human Rad52 protein (HsRad52)-mediated annealing of complementary strands has been studied in detail, but little has been reported on the recombinase activities of HsRad52. For this study, we purified HsRad52 from Escherichia coli. DNase I protection experiments indicated that HsRad52 binds preferentially to single-stranded DNA and protects it against digestion by DNase I. HsRad52 catalyzed D-loop formation in superhelical DNA, as well as strand exchange among oligonucleotide substrates. The formation of a stoichiometric complex between HsRad52 and single-stranded DNA was found to be critical for strand exchange activity, and the coating of both the single- and double-stranded oligonucleotides inhibited the exchange reaction.