title: Selective disruption of the DNA polymerase III α-β complex by the umuD gene products.
abstract: DNA polymerase III (DNA pol III) efficiently replicates the Escherichia coli genome, but it cannot bypass DNA damage. Instead, translesion synthesis (TLS) DNA polymerases are employed to replicate past damaged DNA; however, the exchange of replicative for TLS polymerases is not understood. The umuD gene products, which are up-regulated during the SOS response, were previously shown to bind to the α, β and ε subunits of DNA pol III. Full-length UmuD inhibits DNA replication and prevents mutagenic TLS, while the cleaved form UmuD' facilitates mutagenesis. We show that α possesses two UmuD binding sites: at the N-terminus (residues 1-280) and the C-terminus (residues 956-975). The C-terminal site favors UmuD over UmuD'. We also find that UmuD, but not UmuD', disrupts the α-β complex. We propose that the interaction between α and UmuD contributes to the transition between replicative and TLS polymerases by removing α from the β clamp.
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Silva
authors.forename: Philip
authors.initials: P
authors.lastname: Nevin
authors.forename: Erin A
authors.initials: EA
authors.lastname: Ronayne
authors.forename: Penny J
authors.initials: PJ
authors.lastname: Beuning
mesh_terms: D001665:Binding Sites; D053837:DNA Cleavage; D004258:DNA Polymerase III / Q000737:chemistry / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D011938:Rec A Recombinases / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; C074904:DNA polymerase III, alpha subunit; D011938:Rec A Recombinases; C101139:beta subunit, DNA polymerase III; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli