title: Purification and characterization of HisP, the ATP-binding subunit of a traffic ATPase (ABC transporter), the histidine permease of Salmonella typhimurium. Solubility, dimerization, and ATPase activity.
abstract: The nucleotide-binding subunit, HisP, of the histidine permease, a traffic ATPase (ABC transporter), has been purified as a soluble protein and characterized. Addition of a 6-histidine extension (HisP(His6)) allows a rapid and effective metal affinity purification, giving a 30-fold purification with a yield of 50%. HisP(his6) is indistinguishable from underivatized HisP when incorporated into the permease membrane-bound complex, HisQMP2. Purified HisP(his6) has a strong tendency to precipitate; 5 mM ATP and 20% glycerol maintain it in solution at a high protein concentration. HisP(his6) is active as a dimer, binds ATP with a Kd value of 205 microM, and hydrolyzes it at a rate comparable to that of HisQMP2; in contrast to the latter, it does not display cooperativity for ATP. HisP(his6) has been characterized with respect to substrate and inhibitor specificity and various physico-chemical characteristics. Its pH optimum is 7 and it requires a cation for activity, with Co2+ and Mn2+ being more effective than Mg2+ at lower concentrations but inhibitory in the higher concentration range. In contrast to the intact complex, HisP(his6) is not inhibited by vanadate but is inhibited by N-ethylmaleimide. Neither the soluble receptor, HisJ, nor the transport substrate, histidine, has any effect on the activity.
authors.affiliation: Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California, Berkeley, California 94720-3202, USA.
authors.forename: K
authors.initials: K
authors.lastname: Nikaido
authors.forename: P Q
authors.initials: PQ
authors.lastname: Liu
authors.forename: G F
authors.initials: GF
authors.lastname: Ames
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D026923:Amino Acid Transport Systems, Basic; D001426:Bacterial Proteins; D001693:Biological Transport, Active; D019281:Dimerization; D026901:Membrane Transport Proteins / Q000302:isolation & purification* / Q000378:metabolism; D010957:Plasmids; D011485:Protein Binding; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012486:Salmonella typhimurium / Q000201:enzymology*; D012995:Solubility
chemical_list: D018528:ATP-Binding Cassette Transporters; D026923:Amino Acid Transport Systems, Basic; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; C043828:histidine permease, Bacteria; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases