title: The active form of DNA polymerase V is UmuD'(2)C-RecA-ATP.
abstract: DNA-damage-induced SOS mutations arise when Escherichia coli DNA polymerase (pol) V, activated by a RecA nucleoprotein filament (RecA*), catalyses translesion DNA synthesis. Here we address two longstanding enigmatic aspects of SOS mutagenesis, the molecular composition of mutagenically active pol V and the role of RecA*. We show that RecA* transfers a single RecA-ATP stoichiometrically from its DNA 3'-end to free pol V (UmuD'(2)C) to form an active mutasome (pol V Mut) with the composition UmuD'(2)C-RecA-ATP. Pol V Mut catalyses TLS in the absence of RecA* and deactivates rapidly upon dissociation from DNA. Deactivation occurs more slowly in the absence of DNA synthesis, while retaining RecA-ATP in the complex. Reactivation of pol V Mut is triggered by replacement of RecA-ATP from RecA*. Thus, the principal role of RecA* in SOS mutagenesis is to transfer RecA-ATP to pol V, and thus generate active mutasomal complex for translesion synthesis.
authors.affiliation: Department of Biological Sciences, University of Southern California, University Park, Los Angeles, California 90089-2910, USA.
authors.forename: Qingfei
authors.initials: Q
authors.lastname: Jiang
authors.forename: Kiyonobu
authors.initials: K
authors.lastname: Karata
authors.forename: Roger
authors.initials: R
authors.lastname: Woodgate
authors.forename: Michael M
authors.initials: MM
authors.lastname: Cox
authors.forename: Myron F
authors.initials: MF
authors.lastname: Goodman
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D011938:Rec A Recombinases / Q000378:metabolism*; D013014:SOS Response, Genetics; D015533:Transcriptional Activation
chemical_list: D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; D000255:Adenosine Triphosphate; C078202:UmuC protein, E coli; D011938:Rec A Recombinases; C120926:DNA polymerase V, E coli; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli