Substrate-bound outward-open state of the betaine transporter BetP provides insights into Na+ coupling.

ABSTRACT: The Na(+)-coupled betaine symporter BetP shares a highly conserved fold with other sequence unrelated secondary transporters, for example, with neurotransmitter symporters. Recently, we obtained atomic structures of BetP in distinct conformational states, which elucidated parts of its alternating-access mechanism. Here, we report a structure of BetP in a new outward-open state in complex with an anomalous scattering substrate, adding a fundamental piece to an unprecedented set of structural snapshots for a secondary transporter. In combination with molecular dynamics simulations these structural data highlight important features of the sequential formation of the substrate and sodium-binding sites, in which coordinating water molecules play a crucial role. We observe a strictly interdepend

SUBMITTER: Perez C 

PROVIDER: S-EPMC4745115 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature