Critical role of a conserved transmembrane lysine in substrate recognition by the proton-coupled oligopeptide transporter YjdL

Research output: Contribution to journalJournal articleResearchpeer-review

Johanne M Jensen, Nanda Gowtham Aduri, Bala K Prabhala, Rasmus Jahnsen, Henrik Franzyk, Osman Asghar Mirza

Proton-coupled oligopeptide transporters (POTs) utilize an electrochemical proton gradient to accumulate peptides in the cytoplasm. Changing the highly conserved active-site Lys117 in the Escherichia coli POT YjdL to glutamine resulted in loss of ligand affinity as well as inability to distinguish between a dipeptide ligand and the corresponding dipeptide amide. The radically changed pHBulk profiles of Lys117Gln and Lys117Arg mutants indicate an important role of Lys117 in facilitating protonation of the transporter; a notion that is supported by the close proximity of Lys117 to the conserved ExxERFxYY POT motif previously shown to be involved in proton translocation. These results point toward a novel dual role of Lys117 in direct or indirect interaction with both proton and peptide.

Original languageEnglish
JournalInternational Journal of Biochemistry & Cell Biology
Pages (from-to)311-17
Number of pages7
Publication statusPublished - 24 Sep 2014

ID: 124336908