The MutS protein initiates DNA mismatch repair by recognizing mispaired and unpaired bases embedded in duplex DNA and activating endo- and exonucleases to remove the mismatch. Members of the MutS family also possess a conserved ATPase activity that belongs to the ATP binding cassette (ABC) superfamily. MutS homologs (MSH) have been identified in most prokaryotic and all eukaryotic organisms examined. Prokaryotes have two homologs (MutS1 and MutS2), whereas seven MSH proteins (MSH1 to MSH7) have been identified in eukaryotes. The homodimer MutS1 and heterodimers MSH2-MSH3 and MSH2-MSH6 are primarily involved in mitotic mismatch repair, whereas MSH4-MSH5 is involved in resolution of Holliday junctions during meiosis. All members of the MutS family contain the highly conserved Walker A/B ATPase domain, and many share a common mechanism of action. MutS1, MSH2-MSH3, MSH2-MSH6, and MSH4-MSH5 dimerize to form sliding clamps, and recognition of specific DNA structures or lesions results in ADP/ATP exchange.
Jiyao W et al.(2023). "The conserved domain database in 2023.",