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

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Heidi Asschenfeldt Ernst, Antony Pham, Helle Hald, Jette Sandholm Kastrup, Moazur Rahman, Osman Asghar Mirza

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 22mM while Ala-Ala-Ala was not able to inhibit uptake. In addition, IC(50) values of 0.3mM and 1.5mM 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 31mM, respectively. These results clearly indicate that unlike most POT members characterized to date, including YdgR and YhiP, YjdL shows significantly higher specificity towards dipeptides.
Original languageEnglish
JournalBiochemical and Biophysical Research Communications
Volume389
Issue number1
Pages (from-to)112-116
ISSN0006-291X
DOIs
Publication statusPublished - 2009

Bibliographical note

Keywords: E. coli; POTs; Transport; Peptides; Ligand specificity; YjdL

ID: 14411038