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Structure and activity of human DNA polymerase kappa bypass of 8‐oxoG
Author(s) -
Eoff Robert Lawton,
Irimia Adriana,
Egli Martin,
Guengerich Frederick Peter
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.838.1
Subject(s) - kappa , dna , chemistry , polymerase , dna damage , primer (cosmetics) , dna polymerase , oxidative phosphorylation , biophysics , biochemistry , microbiology and biotechnology , biology , philosophy , linguistics , organic chemistry
Formation of reactive oxygen species and subsequent reactions with biological macromolecules is central to processes that disrupt normal cellular activity and can lead to cellular senescence and tumorigenesis. Here, we present a detailed analysis of the activity and specificity of human DNA polymerase kappa (hpol kappa) bypass opposite the major oxidative adduct 7,8‐dihydro‐8‐oxo‐guanosine (8‐oxoG). Crystal structures of hpol kappa in complex with dATP opposite 8‐oxoG modified DNA reveal a Hoogsteen pairing mode, and complexes with dGTP opposite 8‐oxoG show that hpol kappa does not adopt the "Type II" frameshift mode that is commonly observed in the archaeal DinB homolog Dpo4. Kinetic analysis suggests that hpol kappa ?forms primarily non‐productive complexes when 8‐oxoG is present and greatly favors insertion of dATP opposite the lesion. Mutating the L508 residue in the little finger domain of hpol kappa to lysine results in a shift towards more accurate bypass of 8‐oxoG, reminiscent of results observed with Dpo4. These results provide insight into error‐prone bypass of oxidative damage and reveal the importance of electrostatic interactions between the little finger domain and template DNA during bypass of 8‐oxoG.