DNA mismatch repair complex. Computer model showing the structure of a MutS (Mutator S) protein binding to DNA (deoxyribonucleic acid) during DNA mismatch repair. Mismatch repair involves the correction of mismatched base pairs that can occur during DNA replication. It is necessary to help ensure the overall accuracy of the DNA produced during replication and is essential for combating the adverse effects of damage to the genome. MutS recognises mispaired and unpaired bases in duplex DNA and initiates mismatch repair.