Conformational and dynamic plasticity in substrate-binding proteins underlies selective transport in ABC importers

Boer, Marijn de; Gouridis, Giorgos; Vietrov, Ruslan; Begg, Stephanie L.; Schuurman-Wolters, Gea K.; Husada, Florence; Eleftheriadis, Nikolaos; Poolman, Bert; McDevitt, Christopher A. und Cordes, Thorben (2019): Conformational and dynamic plasticity in substrate-binding proteins underlies selective transport in ABC importers. In: eLife, Bd. 8, e44652

Abstract

Substrate-binding proteins (SBPs) are associated with ATP-binding cassette importers and switch from an open to a closed conformation upon substrate binding, providing specificity for transport. We investigated the effect of substrates on the conformational dynamics of six SBPs and the impact on transport. Using single-molecule FRET, we reveal an unrecognized diversity of plasticity in SBPs. We show that a unique closed SBP conformation does not exist for transported substrates. Instead, SBPs sample a range of conformations that activate transport. Certain non-transported ligands leave the structure largely unaltered or trigger a conformation distinct from that of transported substrates. Intriguingly, in some cases, similar SBP conformations are formed by both transported and non-transported ligands. In this case, the inability for transport arises from slow opening of the SBP or the selectivity provided by the translocator. Our results reveal the complex interplay between ligand-SBP interactions, SBP conformational dynamics and substrate transport.

• Dokumententyp: Zeitschriftenartikel
• EU Funded Grant Agreement Number: 638536
• EU-Projekte: Horizon 2020 > ERC Grants > ERC Starting Grant > ERC Grant 638536: SM-IMPORT - Substrate import at work: single-molecule studies of ABC transporters
• Fakultät: Biologie > Department Biologie I
• Themengebiete: 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften; Biologie
• Sprache: Englisch