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

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-transport

SUBMITTER: de Boer M 

PROVIDER: S-EPMC6450668 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature