title: RecN is a cohesin-like protein that stimulates intermolecular DNA interactions in vitro.
abstract: The bacterial RecN protein is involved in the recombinational repair of DNA double-stranded breaks, and recN mutants are sensitive to DNA-damaging agents. Little is known about the biochemical function of RecN. Protein sequence analysis suggests that RecN is related to the SMC (structural maintenance of chromosomes) family of proteins, predicting globular N- and C-terminal domains connected by an extensive coil-coiled domain. The N- and C-domains contain the nucleotide-binding sequences Walker A and Walker B, respectively. We have purified the RecN protein from Deinococcus radiodurans and characterized its DNA-dependent and DNA-independent ATPase activity. The RecN protein hydrolyzes ATP with a k(cat) of 24 min(-1), and this rate is stimulated 4-fold by duplex DNA but not by single-stranded DNA. This DNA-dependent ATP turnover rate exhibits a dependence on the concentration of RecN protein, suggesting that RecN-RecN interactions are required for efficient ATP hydrolysis, and those interactions are stabilized only by duplex DNA. Finally, we show that RecN stimulates the intermolecular ligation of linear DNA molecules in the presence of DNA ligase. This DNA bridging activity is strikingly similar to that of the cohesin complex, an SMC family member, to which RecN is related.
authors.affiliation: Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, USA.
authors.forename: Emigdio D
authors.initials: ED
authors.lastname: Reyes
authors.forename: Praveen L
authors.initials: PL
authors.lastname: Patidar
authors.forename: Lee A
authors.initials: LA
authors.lastname: Uranga
authors.forename: Angelina S
authors.initials: AS
authors.lastname: Bortoletto
authors.forename: Shelley L
authors.initials: SL
authors.lastname: Lusetti
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D003001:Cloning, Molecular; D003198:Computer Simulation; D004247:DNA / Q000235:genetics*; D004262:DNA Restriction Enzymes / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D034301:Deinococcus / Q000378:metabolism*; D019281:Dimerization; D016680:Genome, Bacterial; D006868:Hydrolysis; D066298:In Vitro Techniques; D007700:Kinetics; D008954:Models, Biological; D008957:Models, Genetic; D011485:Protein Binding
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D004247:DNA; D004262:DNA Restriction Enzymes; C047879:RecN protein, Bacteria; D000251:Adenosine Triphosphatases