TY - JOUR
T1 - Biophysical characterization of the proton-coupled oligopeptide transporter YjdL
AU - Jensen, Johanne Mørch
AU - Simonsen, Fie C.
AU - Mastali, Amir
AU - Hald, Helle
AU - Lillebro, Ida
AU - Diness, Frederik
AU - Olsen, Lars
AU - Mirza, Osman Asghar
N1 - Copyright © 2012 Elsevier Inc. All rights reserved.
PY - 2012/11
Y1 - 2012/11
N2 - Proton-coupled oligopeptide transporters (POTs) utilize the electrochemical proton gradient to facilitate uptake of di- or tripeptide molecules. YjdL is one of four POTs found in Escherichia coli. It has shown an extraordinary preference for di- rather than tripeptides, and is therefore significantly different from prototypical POTs such as the human hPepT1. Nonetheless YjdL contains several highly conserved POT residues, which include Glu388 that is located in the putative substrate binding cavity. Here we present biophysical characterization of WT-YjdL and Glu388Gln. Isothermal titration calorimetrical studies exhibit a K(d) of 14 µM for binding of Ala-Lys to WT-YjdL. Expectedly, no binding could be detected for the tripeptide Ala-Ala-Lys. Surprisingly however, binding could not be detected for Ala-Gln, although earlier studies indicated inhibitory potencies of Ala-Gln to be comparable to Ala-Lys (IC(50) values of 0.6 compared to 0.3mM). Finally, Ala-Lys binding to Glu388Gln was also undetectable which may support a previously suggested role in interaction with the ligand peptide N-terminus.
AB - Proton-coupled oligopeptide transporters (POTs) utilize the electrochemical proton gradient to facilitate uptake of di- or tripeptide molecules. YjdL is one of four POTs found in Escherichia coli. It has shown an extraordinary preference for di- rather than tripeptides, and is therefore significantly different from prototypical POTs such as the human hPepT1. Nonetheless YjdL contains several highly conserved POT residues, which include Glu388 that is located in the putative substrate binding cavity. Here we present biophysical characterization of WT-YjdL and Glu388Gln. Isothermal titration calorimetrical studies exhibit a K(d) of 14 µM for binding of Ala-Lys to WT-YjdL. Expectedly, no binding could be detected for the tripeptide Ala-Ala-Lys. Surprisingly however, binding could not be detected for Ala-Gln, although earlier studies indicated inhibitory potencies of Ala-Gln to be comparable to Ala-Lys (IC(50) values of 0.6 compared to 0.3mM). Finally, Ala-Lys binding to Glu388Gln was also undetectable which may support a previously suggested role in interaction with the ligand peptide N-terminus.
U2 - 10.1016/j.peptides.2012.08.012
DO - 10.1016/j.peptides.2012.08.012
M3 - Journal article
C2 - 22940668
SN - 0196-9781
VL - 38
SP - 89
EP - 93
JO - Peptides
JF - Peptides
IS - 1
ER -