title: Efficiency and accuracy of SOS-induced DNA polymerases replicating benzo[a]pyrene-7,8-diol 9,10-epoxide A and G adducts.
abstract: Nucleotide incorporation fidelity, mismatch extension, and translesion DNA synthesis efficiencies were determined using SOS-induced Escherichia coli DNA polymerases (pol) II, IV, and V to copy 10R and 10S isomers of trans-opened benzo[a]pyrene-7,8-diol 9,10-epoxide (BaP DE) A and G adducts. A-BaP DE adducts were bypassed by pol V with moderate accuracy and considerably higher efficiency than by pol II or IV. Error-prone pol V copied G-BaP DE-adducted DNA poorly, forming A*G-BaP DE-S and -R mismatches over C*G-BaP DE-S and -R correct matches by factors of approximately 350- and 130-fold, respectively, even favoring G*G-BaP DE mismatches over correct matches by factors of 2-4-fold. In contrast, pol IV bypassed G-BaP DE adducts with the highest efficiency and fidelity, making misincorporations with a frequency of 10(-2) to 10(-4) depending on sequence context. G-BaP DE-S-adducted M13 DNA yielded 4-fold fewer plaques when transfected into SOS-induced DeltadinB (pol IV-deficient) mutant cells compared with the isogenic wild-type E. coli strain, consistent with the in vitro data showing that pol IV was most effective by far at copying the G-BaP DE-S adduct. SOS polymerases are adept at copying a variety of lesions, but the relative contribution of each SOS polymerase to copying damaged DNA appears to be determined by the lesion's identity.
authors.affiliation: Department of Biological Sciences and Chemistry, Hedco Molecular Biology Laboratory, University of Southern California, Los Angeles, California 90089-1340, USA.
authors.forename: Xuan
authors.initials: X
authors.lastname: Shen
authors.forename: Jane M
authors.initials: JM
authors.lastname: Sayer
authors.forename: Heiko
authors.initials: H
authors.lastname: Kroth
authors.forename: Ingrid
authors.initials: I
authors.lastname: Ponten
authors.forename: Mike
authors.initials: M
authors.lastname: O'Donnell
authors.forename: Roger
authors.initials: R
authors.lastname: Woodgate
authors.forename: Donald M
authors.initials: DM
authors.lastname: Jerina
authors.forename: Myron F
authors.initials: MF
authors.lastname: Goodman
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000737:chemistry*; D020137:Base Pair Mismatch; D018736:DNA Adducts / Q000235:genetics*; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008956:Models, Chemical; D009153:Mutagens; D009154:Mutation; D013014:SOS Response, Genetics; D014162:Transfection
chemical_list: D018736:DNA Adducts; D009153:Mutagens; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D004259:DNA-Directed DNA Polymerase