Tetramerization of the DNA mismatch repair protein MutS enhances daughter strand incision preferentially in the vicinity of replication errors.

ABSTRACT: DNA replication errors that escape the proofreading activity of the replicative DNA polymerase are repaired by DNA mismatch repair (MMR). The initiation of MMR in Escherichia coli involves the recognition of the mismatch by MutS, binding of MutL, and activation of the endonuclease MutH which incises DNA at a hemi-methylated GATC site. MutS exists in a dimer-tetramer equilibrium, but the function of the tetramer during MMR remains unknown. Here, we used in vitro MutH activation assays to examine the role of MutS in the reaction steps that couple mismatch recognition to daughter strand incision. To study the behavior of different MutS oligomers, we used obligate dimers and tetramers and quantified GATC site incision on circular and linear DNA substrates. Especially in the presence of free DN

SUBMITTER: Mardenborough Y 

PROVIDER: S-EPMC12704291 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature