title: Superhelicity-driven homologous DNA pairing by yeast recombination factors Rad51 and Rad54.
abstract: Yeast Rad51 recombinase has only minimal ability to form D loop. Addition of Rad54 renders D loop formation by Rad51 efficient, even when topologically relaxed DNA is used as substrate. Treatment of the nucleoprotein complex of Rad54 and relaxed DNA with topoisomerases reveals dynamic DNA remodeling to generate unconstrained negative and positive supercoils. DNA remodeling requires ATP hydrolysis by Rad54 and is stimulated by Rad51-DNA nucleoprotein complex. A marked sensitivity of DNA undergoing remodeling to P1 nuclease indicates that the negative supercoils produced lead to transient DNA strand separation. Thus, a specific interaction of Rad54 with the Rad51-ssDNA complex enhances the ability of the former to remodel DNA and allows the latter to harvest the negative supercoils generated for DNA joint formation.
authors.affiliation: Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 78245, USA.
authors.forename: S
authors.initials: S
authors.lastname: Van Komen
authors.forename: G
authors.initials: G
authors.lastname: Petukhova
authors.forename: S
authors.initials: S
authors.lastname: Sigurdsson
authors.forename: S
authors.initials: S
authors.lastname: Stratton
authors.forename: P
authors.initials: P
authors.lastname: Sung
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D004265:DNA Helicases; D045643:DNA Repair Enzymes; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D009690:Nucleic Acid Conformation; D051135:Rad51 Recombinase; D011995:Recombination, Genetic / Q000187:drug effects / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000494:pharmacology; D015003:Yeasts / Q000201:enzymology / Q000235:genetics*
chemical_list: D004271:DNA, Fungal; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; D051135:Rad51 Recombinase; D015719:Single-Strand Specific DNA and RNA Endonucleases; C075468:RAD54 protein, S cerevisiae; D004265:DNA Helicases; D045643:DNA Repair Enzymes