Metal-ion dependence of the active-site conformation of the translesion DNA polymerase Dpo4 fromSulfolobus solfataricus

Abstract

Crystal structures of a binary Mg2+-form Dpo4–DNA complex with 1,N2-etheno-dG in the template strand as well as of ternary Mg2+-form Dpo4–DNA–dCTP/dGTP complexes with 8-oxoG in the template strand have been determined. Comparison of their conformations and active-site geometries with those of the corresponding Ca2+-form complexes revealed that the DNA and polymerase undergo subtle changes as a result of the catalytically more active Mg2+occupying both the A and B sites.