Pyridoxal 5-phosphate inhibition of substrate selectivity mutants of UhpT, the sugar 6-phosphate carrier of Escherichia coli.
In the sugar phosphate transporter UhpT, gain-of-function derivatives that prefer phosphoenolpyruvate (PEP) as substrate have an uncompensated lysine residue on transmembrane segment 11. We show here that these variants are also highly susceptible to substrate-protectable inhibition by covalent modification of lysine with pyridoxal 5-phosphate. The chemical requirements of this interaction provide evidence that the gain-of-function phenotype results from the pairing of the uncompensated lysines in these mutants with the anionic carboxyl group of PEP.
Hall
Jason A
JA
Department of Physiology, Johns Hopkins University Medical School, Baltimore, Maryland 21205-2185, USA.
Maloney
Peter C
PC
D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000737:chemistry; D009004:Monosaccharide Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010728:Phosphoenolpyruvate / Q000378:metabolism; D011732:Pyridoxal Phosphate / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D013379:Substrate Specificity
D029968:Escherichia coli Proteins; D009004:Monosaccharide Transport Proteins; C063498:UhpT protein, E coli; D011732:Pyridoxal Phosphate; D010728:Phosphoenolpyruvate; D008239:Lysine