Full-length Taq MutS was amplified from template pETMutS (22) with primers 5 0 -AAA AAA CAT ATG GAA GGC ATG CTG AAG G-3 0 and 5 0 -AAA AAT AAG CTT CCC CTT CAT GGT ATC CAA GG-3 0 and cloned into the Nde1/HindIII sites of vector pIADL14 (23) to give plasmid pMBP-MutS-H6.