MutL_Trans_MLH1: transducer domain, having a ribosomal S5 domain 2-like fold, found in proteins similar to yeast and human MLH1 (MutL homologue 1). This transducer domain is homologous to the second domain of the DNA gyrase B subunit, which is known to be important in nucleotide hydrolysis and the transduction of structural signals from ATP-binding site to the DNA breakage/reunion regions of the enzymes. MLH1 forms heterodimers with PMS2, PMS1 and MLH3. These three complexes have distinct functions in meiosis. hMLH1-hPMS2 also participates in the repair of all DNA mismatch repair (MMR) substrates. Roles for hMLH1-hPMS1 or hMLH1-hMLH3 in MMR have not been established. Cells lacking hMLH1 have a strong mutator phenotype and display microsatellite instability (MSI). Mutation in hMLH1 causes predisposition to HNPCC, Muir-Torre syndrome and Turcot syndrome (HNPCC variant). Mutation in hMLH1 accounts for a large fraction of HNPCC families.
Jiyao W et al.(2023). "The conserved domain database in 2023.",