title: Role of YiaX2 in L-ascorbate transport in Klebsiella pneumoniae 13882.
abstract: The yiaK-S operon is required for aerobic growth on L-ascorbate in several Enterobacteriaceae. Here we present evidence that the yiaX2 gene belonging to the yiaK-S operon of Klebsiella pneumoniae 13882, which encodes a protein similar to the putative transporters classified as the major facilitator superfamily, is involved in the uptake of L-ascorbate. Concentration kinetic analysis yielded an apparent K(m) of YiaX2 for L-ascorbate of 161.38 +/-8.28 micromol x L(-1) and a Vmax of 3.81 +/- 0.60 nmol x mg(-1) x min(-1). This carrier uses the energy from electrochemical gradients, since it was inhibited by carbonyl cyanide m-chlorophenylhydrazone, a hydrophobic proton conductor that dissipates proton motive force.
authors: Department of Biochemistry and Molecular Biology, Biomedicine Institute University of Barcelona (IBUB), Faculty of Pharmacy, University of Barcelona, Av. Diagonal 643, Barcelona 08028, Spain.
authors: Evangelina
authors: E
authors: Campos
authors: Laura
authors: L
authors: Aguilera
authors: Rosa
authors: R
authors: Giménez
authors: Juan
authors: J
authors: Aguilar
authors: Laura
authors: L
authors: Baldoma
authors: Josefa
authors: J
authors: Badia
mesh_terms: D000332:Aerobiosis; D001205:Ascorbic Acid / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018892:Proton-Motive Force
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D001205:Ascorbic Acid