A Cys-less variant of the bacterial ATP binding cassette protein MalK is functional in maltose transport and regulation.
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.
Hunke
S
S
Humboldt Universität zu Berlin, Institut für Biologie/Bakterienphysiologie, Germany.
Schneider
E
E
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
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