title: [Changing of filamentation dynamics of RecA protein, induced by D112R amino acid substitution or ATP to dATP replacement, results in filament steadiness TO THE RecX protein action].
abstract: It is known that RecX is a negative regulator of RecA protein. We found that the mutant RecA D112R protein exhibits increased resistance to RecX protein comparatively to wild-type RecA protein in vitro and in vivo. Using molecular modeling we showed, that amino acid located in position 112 can not approach RecX closer than 25-28 angstroms. Thus, direct contact between amino acid and RecX is impossible. RecA D112R protein more actively competes with SSB protein for the binding sites on ssDNA and, therefore, differs from the wild-type RecA protein by dynamics of filamentation on ssDNA. On the other hand, after the replacement of ATP by dATP, the wild-type RecA protein, changing the dynamics of filamentation on ssDNA, also becomes more resistant to RecX. Based on these data it is concluded that the dynamics of filamentation has a great, if not dominant role in the stability of RecA filament to RecX relative to the role of RecA-RecX protein-protein interactions discussed earlier. We also propose an improved model of regulation of RecA by RecX protein, where RecA filament elongation along ssDNA is blocked by RecX protein on the ssDNA region, located outside the filament.
authors.forename: A V
authors.initials: AV
authors.lastname: Dudkina
authors.forename: A V
authors.initials: AV
authors.lastname: Shvetsov
authors.forename: I V
authors.initials: IV
authors.lastname: Bakhlanova
authors.forename: D M
authors.initials: DM
authors.lastname: Baĭtin
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D019943:Amino Acid Substitution; D001120:Arginine / Q000737:chemistry* / Q000235:genetics; D001224:Aspartic Acid / Q000737:chemistry* / Q000235:genetics; D004277:DNA, Single-Stranded / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D011938:Rec A Recombinases / Q000737:chemistry* / Q000235:genetics
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C531244:RecX protein, E coli; C476430:SSB protein, E coli; D001224:Aspartic Acid; D000255:Adenosine Triphosphate; D001120:Arginine; D011938:Rec A Recombinases