8TMC
Cryo-EM structure of CorA in complex with conformation-specific synthetic antibody C12 and 20 mM MgCl2, State MG20-2
Summary for 8TMC
| Entry DOI | 10.2210/pdb8tmc/pdb |
| EMDB information | 41384 |
| Descriptor | Cobalt/magnesium transport protein CorA, sAB C12 Heavy Chain, sAB C12 Light Chain, ... (4 entities in total) |
| Functional Keywords | ion channel, magnesium channel, membrane protein |
| Biological source | Thermotoga maritima More |
| Total number of polymer chains | 9 |
| Total formula weight | 319327.14 |
| Authors | Erramilli, S.K.,Perozo, E.,Kossiakoff, A.A. (deposition date: 2023-07-29, release date: 2025-02-12, Last modification date: 2026-02-25) |
| Primary citation | 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 Cited by 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: 41701836DOI: 10.1073/pnas.2512532123 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.3 Å) |
Structure validation
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