Mutational analysis eliminates Glu64 and Glu94 as candidates for 'catalytic carboxylate' in the bacterial ATP-binding-cassette protein MalK.
MalK is the ATP-hydrolyzing subunit of the binding protein-dependent ATP-binding-cassette (ABC) transport system for maltose from Salmonella typhimurium. In a recent hypothesis, Glu64 and Glu94 of MalK were proposed as candidates for 'catalytic carboxylate', common to ATP- and GTP-hydrolyzing proteins [Yoshida and Amano (1995) FEBS Lett. 359, 1-5]. Substitution of both residues and, additionally, Glu74 by either glutamine or glycine and valine, respectively, had no deleterious effect on maltose transport. Thus, our data disprove the above notion.
Stein
A
A
Humboldt-Universität zu Berlin, Institut für Biologie/Bakterienphysiologie, Germany.
Hunke
S
S
Schneider
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E
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002384:Catalysis; D004252:DNA Mutational Analysis; D018698:Glutamic Acid / Q000502:physiology*; D008320:Maltose / Q000378:metabolism; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; C068021:MalK protein, Bacteria; C489399:MalK protein, Salmonella typhimurium; D011993:Recombinant Fusion Proteins; D018698:Glutamic Acid; D008320:Maltose