Translesion synthesis (TLS) is a DNA damage tolerance mechanism, usually involving the Y-family DNA polymerases. We elucidated the structures and some aspects of the mechanisms of one Y-family polymerase, human DNA polymerase eta (hPol ?), bypassing two common DNA lesions, an abasic site (apurinic/apyrimidine, AP) and O6-methylguanine (O6-MeG). Both the steady-state kinetics of single dNTP incorporation opposite an AP site and crystal structures of the hPol ?-DNA complex with an incoming dNTP suggest that incorporation opposite an abasic site by hPol ? obeys a �G-rule� but not an �A-rule�. Mass spectrometry (MS) analysis of primer extension products opposite AP sites identified various lengths of extended products, including full-length extended products and some frame-shift products. MS analysis also revealed that primer extension is very inhibited after incorporation of a G opposite an AP site. However, the primer can further extended after dTTP incorporation, in that oligos having T opposite AP sites are the major full-length extended products.  When bypassing O6-MeG,results from steady-state kinetics, crystallization, and MS analysis of primer extension products suggest that hPol ? shows similar preferences for inserting dCTP and dTTP.

Structure and mechanism of human DNA polymerase eta bypass of an abasic site and <i>O</i><sup>6</sup>-methylguanine

248th National Meeting (2014)

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Structure and mechanism of human DNA polymerase eta bypass of an abasic site and O6-methylguanine

Structure and mechanism of human DNA polymerase eta bypass of an abasic site and O⁶-methylguanine