title: A Cys-less variant of the bacterial ATP binding cassette protein MalK is functional in maltose transport and regulation.
abstract: The cysteine residues of the ABC protein MalK from Salmonella typhimurium maltose transport system (C40, C350, C360) were consecutively replaced by serines. Cys-less MalK was fully functional in maltose transport in vivo. Moreover, the activity of MalK as a repressor of other maltose-regulated genes was also retained. The absence of cysteine residues in the purified protein was verified by its failure to react with fluorescein-5-maleimide. In contrast to purified wild-type MalK, the ATPase activity of the C40S variant was insensitive to inhibition by N-ethylmaleimide.
authors.affiliation: Humboldt Universität zu Berlin, Institut für Biologie/Bakterienphysiologie, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Hunke
authors.forename: E
authors.initials: E
authors.lastname: Schneider
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001692:Biological Transport; D003545:Cysteine / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D008320:Maltose / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D012486:Salmonella typhimurium / Q000201:enzymology; D012694:Serine / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; C068021:MalK protein, Bacteria; C489399:MalK protein, Salmonella typhimurium; D012694:Serine; D008320:Maltose; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D003545:Cysteine; D005033:Ethylmaleimide