The Escherichia coli DNA mismatch repair protein, MutS, binds single b
ase 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 biotinylaled peptide domain has been constructed (MutSb). The
biotinylation lag facilitates MutS detection and binding by avidin wit
hout significantly altering the DNA mismatch binding properties of Mut
S in vitro. We describe a novel and rapid mutation detection method wi
th MutSb using streptavidin-coated magnetic beads and demonstrate that
MutSb can also be used to remove mismatch containing DNA fragments fr
om a mixture of DNA fragments in solution.