A biotinylated MutS fusion protein and its use in a rapid mutation screening technique

The Escherichia coli DNA mismatch repair protein, MutS, binds single base pair mismatches and short deletions in vivo and in vitro. To adapt this protein for mutation detection, a fusion protein of E. coli MutS with a biotinylated peptide domain has been constructed (MutSb). The biotinylation tag facilitates MutS detection and binding by avidin without significantly altering the DNA mismatch binding properties of MutS in vitro. We describe a novel and rapid mutation detection method with MutSb using streptavidin- coated magnetic beads and demonstrate that MutSb can also be used to remove mismatch containing DNA fragments from a mixture of DNA fragments in solution.