Download MendeleyMultispecific Substrate Recognition in a Proton-Dependent Oligopeptide Transporter.
Martinez Molledo, M., Quistgaard, E.M., Flayhan, A., Pieprzyk, J., Low, C.(2018) Structure 26: 467-476.e4
- PubMed: 29429879
- DOI: https://doi.org/10.1016/j.str.2018.01.005
- Primary Citation of Related Structures:
5OXK, 5OXL, 5OXM, 5OXN, 5OXO, 5OXP, 5OXQ, 6EIA - PubMed 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 can be further aided by adjustment of the position of the peptide itself. Finally, structures were also determined in complex with adventitiously bound HEPES, polyethylene glycol, and phosphate molecules, which further underline the adaptability of the binding site.
Organizational Affiliation:
Centre for Structural Systems Biology (CSSB), DESY and European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany.
