Oligonucleotide-directed, site-specific mutagenesis has been utilized to modify the melB gene of Escherichia coli such that each of the seven His residues in the melibiose permease has been replaced ...

Heme, a major iron source, is transported through the outer membrane of Gram-negative bacteria by specific heme/hemoprotein receptors and through the inner membrane by heme-specific, periplasmic, ...

Lactose permease (LacY) of Escherichia coli stands as a prototype of the major facilitator superfamily, employing the energy of a proton gradient to mediate the uptake of sugars against their ...