title: Components of histidine transport: histidine-binding proteins and hisP protein.
abstract: The high-affinity (K(m) = 3 x 10(-8) M) transport system for histidine in Salmonella typhimurium has been resolved into three components: J, K, and P. J, which is a histidine-binding protein released by osmotic shock, is specified by the hisJ gene: hisJ mutants lack the binding protein and are defective in histidine transport. Another class of mutants-dhuA, which is closely linked to hisJ-has five times the normal level of binding protein and has an increased rate of histidine transport. P, which is a protein specified by the hisP gene, is required for J binding protein to be operative in transport. hisP mutants, though defective in transport, have normal levels of J binding protein. K, a third transport component, works in parallel to J, and also requires the P protein in order to be operative in transport. A second histidine-binding protein has been found but its relation to K is unclear. hisJ, dhuA, and hisP have been mapped and are in a cluster (near purF) on the S. typhimurium chromosome.
mesh_terms: D001692:Biological Transport; D002848:Chromatography, DEAE-Cellulose; D002874:Chromosome Mapping; D006639:Histidine / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding; D012486:Salmonella typhimurium / Q000378:metabolism*; D014316:Tritium
chemical_list: D014316:Tritium; D006639:Histidine