title: DNA flap creation by the RarA/MgsA protein of Escherichia coli.
abstract: We identify a novel activity of the RarA (also MgsA) protein of Escherichia coli, demonstrating that this protein functions at DNA ends to generate flaps. A AAA+ ATPase in the clamp loader clade, RarA protein is part of a highly conserved family of DNA metabolism proteins. We demonstrate that RarA binds to double-stranded DNA in its ATP-bound state and single-stranded DNA in its apo state. RarA ATPase activity is stimulated by single-stranded DNA gaps and double-stranded DNA ends. At these double-stranded DNA ends, RarA couples the energy of ATP binding and hydrolysis to separating the strands of duplex DNA, creating flaps. We hypothesize that the creation of a flap at the site of a leading strand discontinuity could, in principle, allow DnaB and the associated replisome to continue DNA synthesis without impediment, with leading strand re-priming by DnaG. Replication forks could thus be rescued in a manner that does not involve replisome disassembly or reassembly, albeit with loss of one of the two chromosomal products of a replication cycle.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA.
authors.forename: Tyler H
authors.initials: TH
authors.lastname: Stanage
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA.
authors.forename: Asher N
authors.initials: AN
authors.lastname: Page
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Cox
mesh_terms: D020856:AT Rich Sequence; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000378:metabolism*
chemical_list: D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; C000621718:MgsA protein, E coli