PMID: 28436435

Authors:

Nie R, Stark S, Symersky J, Kaplan RS, Lu M

Title:

Structure and function of the divalent anion/Na+ symporter from Vibrio cholerae and a humanized variant.

Journal:

Nat Commun. 2017 Apr 24;8:15009. doi: 10.1038/ncomms15009.

Abstract:

Integral membrane proteins of the divalent anion/Na+ symporter (DASS) family translocate dicarboxylate, tricarboxylate or sulphate across cell membranes, typically by utilizing the preexisting Na+ gradient. The molecular determinants for substrate recognition by DASS remain obscure, largely owing to the absence of any substrate-bound DASS structure. Here we present 2.8-A resolution X-ray structures of VcINDY, a DASS from Vibrio cholerae that catalyses the co-transport of Na+ and succinate. These structures portray the Na+-bound VcINDY in complexes with succinate and citrate, elucidating the binding sites for substrate and two Na+ ions. Furthermore, we report the structures of a humanized variant of VcINDY in complexes with succinate and citrate, which predict how a human citrate-transporting DASS may interact with its bound substrate. Our findings provide insights into metabolite transport by DASS, establishing a molecular basis for future studies on the regulation of this transport process.