Figure 2

(A). E. coli MutY structure bound to adenine base (RCSB ID 1MUD) with thymine docked into the binding pocket as proposed by Mol et al.[23] for Mig.MthI. The residues of EcMutY known to be important for adenine recognition (E37, V45, and Q182) and the adenine and thymine bases are colored by atom type except the carbons in the docked thymine are colored yellow. Residues homologous to those residues in Mig.MthI proposed to be important in forming a hydrophobic pocket around the thymine methyl group (marked Me) are colored yellow. (B). The active site of Mig.MthI with thymine docked in according to the proposed orientation and hydrogen-bonding scheme [23]. The adenine from the EcMutY structure is included as a reference to show the relative position of key residues in the active site. As in (A), residues implicated in solvating the thymine methyl group are colored yellow. Y126, which is proposed to form a hydrogen bond with O2 of thymine is not pictured for reasons of clarity. (C). A space-filling model of thymine docked into the EcMutY active site, with an emphasis on interactions with the methyl group (Me). (D). A space-filling model of thymine docked into the Mig.MthI active site as proposed [23].