Multispecific Substrate Recognition in a Proton-Dependent Oligopeptide Transporter.

ABSTRACT: Proton-dependent oligopeptide transporters (POTs) are important for uptake of dietary di- and tripeptides in many organisms, and in humans are also involved in drug absorption. These transporters accept a wide range of substrates, but the structural basis for how different peptide side chains are accommodated has so far remained obscure. Twenty-eight peptides were screened for binding to PepT_St from Streptococcus thermophilus, and structures were determined of PepT_St in complex with four physicochemically diverse dipeptides, which bind with millimolar affinity: Ala-Leu, Phe-Ala, Ala-Gln, and Asp-Glu. The structures show that PepT_St can adapt to different peptide side chains through movement of binding site residues and water molecules, and that a good fit c

SUBMITTER: Martinez Molledo M 

PROVIDER: S-EPMC5845931 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature