Publications

• Ligand binding analyses of the putative peptide transporter YjdL from E. coli display a significant selectivity towards dipeptides.

  Ernst H.A., Pham A., Hald H., Kastrup J.S., Rahman M., Mirza O.

  Proton-dependent oligopeptide transporters (POTs) are secondary active transporters that couple the inwards translocation of di- and tripeptides to inwards proton translocation. Escherichia coli contains four genes encoding the putative POT proteins YhiP, YdgR, YjdL and YbgH. We have over-expresse ... >> More

  Proton-dependent oligopeptide transporters (POTs) are secondary active transporters that couple the inwards translocation of di- and tripeptides to inwards proton translocation. Escherichia coli contains four genes encoding the putative POT proteins YhiP, YdgR, YjdL and YbgH. We have over-expressed the previously uncharacterized YjdL and investigated the peptide specificity by means of uptake inhibition. The IC(50) value for the dipeptide Ala-Ala was measured to 22 mM while Ala-Ala-Ala was not able to inhibit uptake. In addition, IC(50) values of 0.3 mM and 1.5 mM were observed for Ala-Lys and Tyr-Ala, respectively, while the alanyl-extended tripeptides Ala-Lys-Ala, Ala-Ala-Lys, Ala-Tyr-Ala and Tyr-Ala-Ala displayed values of 8, >50, 31 and 31 mM, respectively. These results clearly indicate that unlike most POT members characterized to date, including YdgR and YhiP, YjdL shows significantly higher specificity towards dipeptides. << Less

  Biochem. Biophys. Res. Commun. 389:112-116(2009) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Electrophysiological characteristics of the proton-coupled peptide transporter PEPT2 cloned from rat brain.

  Wang H., Fei Y.J., Ganapathy V., Leibach F.H.

  We have cloned a peptide transporter from rat brain and found it to be identical to rat kidney PEPT2. In the present study we characterize the transport function of the rat brain PEPT2, with special emphasis on electrophysiological properties and interaction with N-acetyl-L-aspartyl-L-glutamate (N ... >> More

  We have cloned a peptide transporter from rat brain and found it to be identical to rat kidney PEPT2. In the present study we characterize the transport function of the rat brain PEPT2, with special emphasis on electrophysiological properties and interaction with N-acetyl-L-aspartyl-L-glutamate (NAAG). When heterologously expressed in HeLa cells and in SK-N-SH cells, PEPT2 transports several dipeptides but not free amino acids in the presence of a proton gradient. NAAG competes with other peptides for the PEPT2-mediated transport process. When PEPT2 is expressed in Xenopus laevis oocytes, substrate-induced inward currents are detectable with dipeptides of differing charge in the presence of a proton gradient. Proton activation kinetics are similar for differently charged peptides. NAAG is a transportable substrate for PEPT2, as evidenced by NAAG-induced currents. The Hill coefficient for protons for the activation of the transport of differently charged peptides, including NAAG, is 1. Although the peptide-to-proton stoichiometry for negatively charged peptides is 1, the transport nonetheless is associated with transfer of positive charge into the oocyte, as indicated by peptide-induced inward currents. << Less

  Am J Physiol 275:C967-75(1998) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.