8TMC

Cryo-EM structure of CorA in complex with conformation-specific synthetic antibody C12 and 20 mM MgCl2, State MG20-2

8TMC の概要

• エントリーDOI: 10.2210/pdb8tmc/pdb
• EMDBエントリー: 41384
• 分子名称: Cobalt/magnesium transport protein CorA, sAB C12 Heavy Chain, sAB C12 Light Chain, ... (4 entities in total)
• 機能のキーワード: ion channel, magnesium channel, membrane protein
• 由来する生物種: Thermotoga maritima; 詳細
• タンパク質・核酸の鎖数: 9
• 化学式量合計: 319327.14

構造登録者

Erramilli, S.K.,Perozo, E.,Kossiakoff, A.A. (登録日: 2023-07-29, 公開日: 2025-02-12, 最終更新日: 2026-02-25)

主引用文献

Erramilli, S.K.,Nosol, K.,Pietrzak-Lichwa, K.,Schmandt, N.,Li, T.,Tokarz, P.,Hou, J.,Zhao, M.,Perozo, E.,Kossiakoff, A.A.
Conformational ensembles of the magnesium channel CorA reveal structural basis for channel gating.
Proc.Natl.Acad.Sci.USA, 123:e2512532123-e2512532123, 2026

PubMed Abstract: In prokaryotes, CorA is the primary influx pathway for magnesium, a critical divalent cation in cellular physiology and biochemistry. Mechanistic studies show that homopentameric CorA is regulated through an intracellular [Mg]-dependent negative feedback loop, involving the asymmetric participation of individual subunits. To understand the connection between asymmetry and activation, we used single-particle cryo-EM to solve sixteen structures of nanodisc-reconstituted CorA. We utilized conformation-specific synthetic antibodies to stabilize subtle but significant conformational differences in the cryo-EM structures. Our results demonstrate that CorA exists as a set of conformational ensembles, where population size inversely correlates with intracellular Mg concentration. These ensembles include channels with a variety of pore conformations, both constricted and dilated, suggesting a spectrum of active CorA functional states. The ensembles connect asymmetric structural transitions in the cytoplasmic domain with conformational changes in the permeation pathway via an electrostatic network, ultimately controlling channel-gating events. We believe that these results establish a framework for understanding magnesium homeostasis in prokaryotic systems.

PubMed: 41701836
DOI: 10.1073/pnas.2512532123

実験手法

ELECTRON MICROSCOPY (3.3 Å)