title: Structural and dynamic characterization of polymerase κ's minor groove lesion processing reveals how adduct topology impacts fidelity.
abstract: DNA lesion bypass polymerases process different lesions with varying fidelities, but the structural, dynamic, and mechanistic origins of this phenomenon remain poorly understood. Human DNA polymerase κ (Polκ), a member of the Y family of lesion bypass polymerases, is specialized to bypass bulky DNA minor groove lesions in a predominantly error-free manner, by housing them in its unique gap. We have investigated the role of the unique Polκ gap and N-clasp structural features in the fidelity of minor groove lesion processing with extensive molecular modeling and molecular dynamics simulations to pinpoint their functioning in lesion bypass. Here we consider the N(2)-dG covalent adduct derived from the carcinogenic aromatic amine, 2-acetylaminofluorene (dG-N(2)-AAF), that is produced via the combustion of kerosene and diesel fuel. Our simulations reveal how the spacious gap directionally accommodates the lesion aromatic ring system as it transits through the stages of incorporation of the predominant correct partner dCTP opposite the damaged guanine, with preservation of local active site organization for nucleotidyl transfer. Furthermore, flexibility in Polκ's N-clasp facilitates the significant misincorporation of dTTP opposite dG-N(2)-AAF via wobble pairing. Notably, we show that N-clasp flexibility depends on lesion topology, being markedly reduced in the case of the benzo[a]pyrene-derived major adduct to N(2)-dG, whose bypass by Polκ is nearly error-free. Thus, our studies reveal how Polκ's unique structural and dynamic properties can regulate its bypass fidelity of polycyclic aromatic lesions and how the fidelity is impacted by lesion structures.
authors.affiliation: Department of Biology and ‡Department of Chemistry, New York University , 100 Washington Square East, New York, New York 10003, United States.
authors.forename: Lee
authors.initials: L
authors.lastname: Lior-Hoffmann
authors.forename: Shuang
authors.initials: S
authors.lastname: Ding
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Geacintov
authors.forename: Yingkai
authors.initials: Y
authors.lastname: Zhang
authors.forename: Suse
authors.initials: S
authors.lastname: Broyde
mesh_terms: D015073:2-Acetylaminofluorene / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D020137:Base Pair Mismatch; D020134:Catalytic Domain; D018736:DNA Adducts / Q000737:chemistry / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry* / Q000378:metabolism*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D013379:Substrate Specificity; D000099270:Y-Family DNA Polymerases
chemical_list: D015073:2-Acetylaminofluorene; D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase; D003849:Deoxyguanosine; C018776:N-(deoxyguanosin-8-yl)acetylaminofluorene; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases