Function
DNA mismatch repair proteins are key players in genomic stability by signalling mismatches occurring during DNA replication and recombination[1] .
MutS is prokaryotic and recognizes base-base mismatches and small insertion/deletion mispairs[2] .
MutL enhances recognition of mismatches[3]
MutH is the eukaryotic homolog of MutS
MLH1, MLH3, PMS1, PMS2 are the human homologs of MutL[4]
Disease
Mutations in DNA mismatch repair proteins cause hereditary colorectal cancer and loss of these proteins cause significant fraction of sporadic cancers[5].
Structural highlights
MutS is composed of several domains: N-terminal mismatch-recognition domain; connector domain; core domain; clamp domain; ATPase domain; helix-turn-helix domain. The complex between E. coli MutS and DNA in the scanning mode shows the straight DNA strand clamped between the two MutS monomers and held by the mismatch binding domain (residues 1-115) and the clamp domain (residues 444-503 [6]. In the 3D structure of the mismatch-bound MutS, the DNA strand is kinked by 60 degrees.
3D structures of DNA mismatch repair protein
DNA mismatch repair protein 3D structures