National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)
R01NS108151
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM121994
米国
National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Disease (NIH/NIDDK)
R01DK099023
米国
American Cancer Society
129844-PF-17-135-01-TBE
米国
Department of Defense (DOD, United States)
W81XWH-16-1-0153
米国
引用
ジャーナル: Nat Commun / 年: 2022 タイトル: Structural basis of ion - substrate coupling in the Na-dependent dicarboxylate transporter VcINDY. 著者: David B Sauer / Jennifer J Marden / Joseph C Sudar / Jinmei Song / Christopher Mulligan / Da-Neng Wang / 要旨: 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 ...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, including HPb, TM10b and the substrate clamshell motifs. Upon sodium binding, these regions become structurally ordered and create a proper binding site for the substrate. Taken together, these results provide strong evidence that VcINDY's conformational selection mechanism is a result of the sodium-dependent formation of the substrate binding site.
EMPIAR-10969 (タイトル: Particle stacks for VcINDY in 300mM NaCl / Data size: 35.4 Data #1: Particle stack of VcINDY in 300 mM NaCl [picked particles - multiframe - processed])