(A) Overlay of the peptide binding site of NatA (orange) and NatD (cyan with magenta histone substrate).
(B) Electrostatic potential surface of the NatA active site with a bound covalently linked bisubstrate inhibitor. The N-terminal serine of the substrate peptide is shown in orange, and the acetyl-CoA moiety of the bisubstrate inhibitor is in white.
(C) Electrostatic potential surface of the NatD active site. The N-terminal serine of the substrate peptide is shown in magenta, and acetyl-CoA is in orange. Waters are shown as red spheres. Acetyl-CoA was modeled into the figure by aligning the binary and ternary NatD structures.