Complete nucleotide sequence and identification of membrane components of the histidine transport operon of S. typhimurium.

The nucleotide sequence of the entire histidine transport operon from Salmonella typhimurium has been determined and is shown to consist of four genes, hisJ, hisQ, hisM and hisP. This operon provides the only example of a binding protein-dependent transport system for which the total number of protein components is known. Determination of the amino acid compositions and sequences of these four transport proteins, together with analysis of various transport mutants, allows us to propose a molecular model for binding protein-dependent transport.