Structural basis of ion - substrate coupling in the Na⁺-dependent dicarboxylate transporter VcINDY.

ABSTRACT: The Na⁺-dependent dicarboxylate transporter from Vibrio cholerae (VcINDY) is a prototype for the divalent anion sodium symporter (DASS) family. While the utilization of an electrochemical Na⁺ gradient to power substrate transport is well established for VcINDY, the structural basis of this coupling between sodium and substrate binding is not currently understood. Here, using a combination of cryo-EM structure determination, succinate binding and site-directed cysteine alkylation assays, we demonstrate that the VcINDY protein couples sodium- and substrate-binding via a previously unseen cooperative mechanism by conformational selection. In the absence of sodium, substrate binding is abolished, with the succinate binding regions exhibiting increased flexibility, includi

SUBMITTER: Sauer DB 

PROVIDER: S-EPMC9098524 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature