Characterization of Escherichia coli type 1 pilus mutants with altered binding specificities

PCR mutagenesis and a unique enrichment scheme were used to obtain two muta nts, each with a single lesion in fimH, the chromosomal gene that encodes t he adhesin protein (FimH) of Escherichia coli type 1 pill, These mutants we re noteworthy in part because both were altered in the normal range of cell types bound by FimH, One mutation altered an amino acid at a site previous ly shown to be involved in temperature-dependent binding, and the other alt ered an amino acid lining the predicted FimH binding pocket.