title: Na+-coupled transport of melibiose in Escherichia coli: analysis of mutants with altered cation specificity.
abstract: Melibiose transport via the melibiose transport system of Escherichia coil utilizes either H+ or Na+ as a coupling cation. This system may represent a evolutional transition state between H+-substrate cotransport (bacteria type) and Na+-substrate cotransport (animal type). We have isolated mutants which showed altered cation specificity for melibiose transport. The melibiose carrier of the mutants has lost the ability to recognize H+. This communication describes the properties of the melibiose transport system and the properties of the mutants.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001693:Biological Transport, Active; D002414:Cations, Monovalent; D004187:Disaccharides / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008553:Melibiose / Q000378:metabolism*; D009154:Mutation; D006180:Proton-Translocating ATPases; D012964:Sodium / Q000378:metabolism*
chemical_list: D002414:Cations, Monovalent; D004187:Disaccharides; D008553:Melibiose; D012964:Sodium; D000251:Adenosine Triphosphatases; D006180:Proton-Translocating ATPases