The predicted tertiary protein structure of mtMutS and its similarity to predicted and experimentally determined MutS structures. (A) The predicted monomer structure of the mtMutS protein, as determined by the I-TASSER database. (B) The predicted monomer structure of the HNH-containing Acanthamoeba polyphaga mimiviral MutS protein. (C) The crystal structure of a monomer of MutS from E. coli, as determined by . Colours correspond to the domains identified in Figure 4: Red = Domain I, Blue = Domain III, Yellow = Domain V, Green = HNH endonuclease domain.