6VAM image
Entry Detail
PDB ID:
6VAM
EMDB ID:
Title:
Cryo-EM structure of octameric chicken CALHM1
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2019-12-17
Release Date:
2020-01-29
Method Details:
Experimental Method:
Resolution:
3.63 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Green fluorescent protein,CALHM1 chimera
Chain IDs:A, B, C, D, E, F, G, H
Chain Length:638
Number of Molecules:8
Biological Source:Aequorea victoria, Gallus gallus
Ligand Molecules
Primary Citation
Structure and assembly of calcium homeostasis modulator proteins.
Nat.Struct.Mol.Biol. 27 150 159 (2020)
PMID: 31988524 DOI: 10.1038/s41594-019-0369-9

Abstact

The biological membranes of many cell types contain large-pore channels through which a wide variety of ions and metabolites permeate. Examples include connexin, innexin and pannexin, which form gap junctions and/or bona fide cell surface channels. The most recently identified large-pore channels are the calcium homeostasis modulators (CALHMs), through which ions and ATP permeate in a voltage-dependent manner to control neuronal excitability, taste signaling and pathologies of depression and Alzheimer's disease. Despite such critical biological roles, the structures and patterns of their oligomeric assembly remain unclear. Here, we reveal the structures of two CALHMs, chicken CALHM1 and human CALHM2, by single-particle cryo-electron microscopy (cryo-EM), which show novel assembly of the four transmembrane helices into channels of octamers and undecamers, respectively. Furthermore, molecular dynamics simulations suggest that lipids can favorably assemble into a bilayer within the larger CALHM2 pore, but not within CALHM1, demonstrating the potential correlation between pore size, lipid accommodation and channel activity.

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Primary Citation of related structures