Electrostatic potential surfaces of the pol m active site with cognate or non-cognate incoming nucleotides. (A) A:dTTP
cognate system; (B) A:dCTP non-cognate system; (C) A:dATP non-cognate system; (D) A(syn):dATP non-cognate system; (E) A:dGTP non-cognate
system; (F) A(syn):dGTP non-cognate system; (G) T:dATP cognate system; (H) T:dCTP non-cognate system; (I) T:dGTP non-cognate system. The two
cognate systems (A and G) are labeled in yellow.