Active site conformation in the ternary hpol η insertion step complex with dAMPnPP opposite 1,N2-ε−G in the 5′-T(εG)A-3′ template sequence context (oligonucleotide 1).A, view into the DNA major groove. B, rotated by 90° and viewed perpendicular to the adenine and adduct base planes. Selected active site residues are colored by atom with carbon atoms shown in purple (1,N2-ε−G), orange (incoming dAMPnPP), or pink (Arg-61 and Gln-38 from the finger domain and Asp/Glu coordinating Mg2+ ions that are shown as light green spheres). The remaining template and primer residues are colored in yellow and H-bonds involving the incoming nucleotide are drawn with dashed lines.