Figure 3.

Protein–DNA interactions. (a) The ∼60° bend in the DNA is the result of asymmetric intercalation from the major groove, of a hydrophobic wedge formed by Phe67, Trp68 and Trp86, between the G:T mismatch and the central A:T base pair of the hemi-deaminated/hemi-methylated dcm sequence. The positions of the terminal thymidine 5′ phosphate at the nick site is indicated. (b) The unique pattern of hydrogen bond accepting groups presented by the major groove edge of the ‘wobble’ conformation G:T mismatch is recognised by hydrogen bonds from the ε-amino of Lys89 and the amide-NH₂ of Asn93.