Biological Assembly 1  

Global Symmetry: Cyclic - C7  (3D View)
Global Stoichiometry: Homo 7-mer - A7 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: electron microscopy

Macromolecule Content

• Total Structure Weight: 663.23 kDa 
• Atom Count: 17,465 
• Modelled Residue Count: 2,097 
• Deposited Residue Count: 5,775 
• Unique protein chains: 1

 8DXP

Structure of LRRC8C-LRRC8A(IL125) Chimera, Class 3

• PDB DOI:  https://doi.org/10.2210/pdb8DXP/pdb
• EM Map EMD-27772: EMDB EMDataResource

• Classification: TRANSPORT PROTEIN
• Organism(s): Homo sapiens
• Expression System: Spodoptera frugiperda
• Mutation(s): No 
• Membrane Protein: Yes  PDBTMmpstruc


• Deposited: 2022-08-02 Released: 2023-03-22 
• Deposition Author(s): Takahashi, H., Yamada, T., Denton, J.S., Strange, K., Karakas, E.
• Funding Organization(s): National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Disease (NIH/NIDDK)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.70 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Cryo-EM structures of a LRRC8 chimera with native functional properties reveal heptameric assembly.

Takahashi, H., Yamada, T., Denton, J.S., Strange, K., Karakas, E.

(2023) Elife 12

• PubMed: 36897307 
• DOI: https://doi.org/10.7554/eLife.82431
• Primary Citation of Related Structures:  
  8DXN, 8DXO, 8DXP, 8DXQ, 8DXR


• PubMed Abstract: 
  

Volume-regulated anion channels (VRACs) mediate volume regulatory Cl ^- and organic solute efflux from vertebrate cells. VRACs are heteromeric assemblies of LRRC8A-E proteins with unknown stoichiometries. Homomeric LRRC8A and LRRC8D channels have a small pore, hexameric structure. However, these channels are either non-functional nor exhibit abnormal regulation and pharmacology, limiting their utility for structure-function analyses. We circumvented these limitations by developing novel homomeric LRRC8 chimeric channels with functional properties consistent with those of native VRAC/LRRC8 channels. We demonstrate here that the LRRC8C-LRRC8A(IL1 ²⁵ ) chimera comprising LRRC8C and 25 amino acids unique to the first intracellular loop (IL1) of LRRC8A has a heptameric structure like that of homologous pannexin channels. Unlike homomeric LRRC8A and LRRC8D channels, heptameric LRRC8C-LRRC8A(IL1 ²⁵ ) channels have a large-diameter pore similar to that estimated for native VRACs, exhibit normal DCPIB pharmacology, and have higher permeability to large organic anions. Lipid-like densities are located between LRRC8C-LRRC8A(IL1 ²⁵ ) subunits and occlude the channel pore. Our findings provide new insights into VRAC/LRRC8 channel structure and suggest that lipids may play important roles in channel gating and regulation.

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Organizational Affiliation: 

Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Volume-regulated anion channel subunit LRRC8C,Volume-regulated anion channel subunit LRRC8A	A, B, C, D, E, F, G	825	Homo sapiens	Mutation(s): 0  Gene Names: LRRC8C, AD158, FAD158, LRRC8A, KIAA1437, LRRC8, SWELL1, UNQ221/PRO247 Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for Q8TDW0 (Homo sapiens) Explore Q8TDW0  Go to UniProtKB:  Q8TDW0
PHAROS:  Q8TDW0
Find proteins for Q8IWT6 (Homo sapiens) Explore Q8IWT6  Go to UniProtKB:  Q8IWT6
PHAROS:  Q8IWT6
UniProt Groups	Q8IWT6Q8TDW0

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.70 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX
RECONSTRUCTION	cryoSPARC

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2023-03-22 
Deposition Author(s): Takahashi, H., Yamada, T., Denton, J.S., Strange, K., Karakas, E.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Disease (NIH/NIDDK)	United States	DK51610

Revision History  

• Version 1.0: 2023-03-22
  Type: Initial release