Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8323102 | The International Journal of Biochemistry & Cell Biology | 2014 | 7 Pages |
Abstract
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.
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Authors
Johanne M. Jensen, Nanda G. Aduri, Bala K. Prabhala, Rasmus Jahnsen, Henrik Franzyk, Osman Mirza,