Crystal structures of MutS-mismatch complex. (a) Crystal structure of E. coli MutS bound to a G:T-mismatched heteroduplex (PDB ID: 1E3M). One of the 2 subunits of E. coli MutS is shown in color. DNA is shown in salmon. Domains I, II, III, IV, and V are shown in red, pink, violet, purple blue, and blue, respectively. Domains I, IV, and V are responsible for mismatch recognition, double-stranded DNA binding, and dimerization/ATP binding, respectively. (b) The mismatch-recognition site in E. coli MutS-G:T mismatch complex. The mismatch-recognizing phenylalanine residue (Phe36) and G:T mismatch are shown in red and blue, respectively. (c) Crystal structure of human (PDB ID: 2O8B), which is comprised of full-length MSH2 and a protease-resistant fragment of MSH6 lacking the first 340 amino acid residues. MSH2 is shown in white and MSH6 is in color. Mismatch-binding, Connector, Levers, Clamp, and ATPase domains are colored in red, pink, magenta, purple, and blue, respectively. (d) The mismatch-recognition site in human -G:T mismatch complex. Phe432 and G:T mismatch is shown in red and blue, respectively.
