title: Preferential misincorporation of purine nucleotides by human DNA polymerase eta opposite benzo[a]pyrene 7,8-diol 9,10-epoxide deoxyguanosine adducts.
abstract: Human DNA polymerase eta was used to copy four stereoisomeric deoxyguanosine (dG) adducts derived from benzo[a]pyrene 7,8-diol 9,10-epoxide (diastereomer with the 7-hydroxyl group and epoxide oxygen trans (BaP DE-2)). The adducts, formed by either cis or trans epoxide ring opening of each enantiomer of BaP DE-2 by N(2) of dG, were placed at the fourth nucleotide from the 5'-end in two 16-mer sequence contexts, 5' approximately CG*A approximately and 5' approximately GG*T. poleta was remarkably error prone at all four diol epoxide adducts, preferring to misincorporate G and A at frequencies 3- to more than 50-fold greater than the frequencies for T or the correct C, although the highest rates were 60-fold below the rate of incorporation of C opposite a non-adducted G. Anti to syn rotation of the adducted base, consistent with previous NMR data for a BaP DE-2 dG adduct placed just beyond a primer terminus, provides a rationale for preferring purine misincorporation. Extension of purine misincorporations occurred preferentially, but extension beyond the adduct site was weak with V(max)/K(m) values generally 10-fold less than for misincorporation. Mostly A was incorporated opposite (+)-BaP DE-2 dG adducts, which correlates with published observations that G --> T is the most common type of mutation that (+)-BaP DE-2 induces in mammalian cells.
authors.affiliation: Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Dominic
authors.initials: D
authors.lastname: Chiapperino
authors.forename: Heiko
authors.initials: H
authors.lastname: Kroth
authors.forename: Irene H
authors.initials: IH
authors.lastname: Kramarczuk
authors.forename: Jane M
authors.initials: JM
authors.lastname: Sayer
authors.forename: Chikahide
authors.initials: C
authors.lastname: Masutani
authors.forename: Fumio
authors.initials: F
authors.lastname: Hanaoka
authors.forename: Donald M
authors.initials: DM
authors.lastname: Jerina
authors.forename: Albert M
authors.initials: AM
authors.lastname: Cheh
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000031:analogs & derivatives* / Q000378:metabolism*; D001665:Binding Sites; D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry* / Q000378:metabolism*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D011687:Purines / Q000737:chemistry*; D013237:Stereoisomerism; D000099270:Y-Family DNA Polymerases
chemical_list: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase; D003849:Deoxyguanosine; D011687:Purines; C418058:benzo(a)pyrene 7,8-diol-9,10-epoxide-N2-deoxyguanosine; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases; C030985:purine