7RHS

Cryo-EM structure of apo-state of human CNGA3/CNGB3 channel

Summary for 7RHS

• Entry DOI: 10.2210/pdb7rhs/pdb
• EMDB information: 24468
• Descriptor: Cyclic nucleotide-gated cation channel alpha-3, Cyclic nucleotide-gated cation channel beta-3, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (4 entities in total)
• Functional Keywords: cone, cng channel, cgmp, transport protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 4
• Total formula weight: 336836.96

Authors

Zheng, X.,Yang, J. (deposition date: 2021-07-18, release date: 2022-03-02, Last modification date: 2025-05-28)

Primary citation

Zheng, X.,Hu, Z.,Li, H.,Yang, J.
Structure of the human cone photoreceptor cyclic nucleotide-gated channel.
Nat.Struct.Mol.Biol., 29:40-46, 2022

PubMed Abstract: Cyclic nucleotide-gated (CNG) channels transduce light-induced chemical signals into electrical signals in retinal cone and rod photoreceptors. Structures of native CNG channels, which are heterotetramers formed by CNGA and CNGB subunits, have not been obtained. In the present study, we report a high-resolution cryo-electron microscopy structure of the human cone CNG channel in the apo closed state. The channel contains three CNGA3 and one CNGB3 subunits. Arg403 in the pore helix of CNGB3 projects into an asymmetric selectivity filter and forms hydrogen bonds with two pore-lining backbone carbonyl oxygens. Arg442 in S6 of CNGB3 protrudes into and occludes the pore below the hydrophobic cavity gate previously observed in homotetrameric CNGA channels. It is interesting that Arg403Gln is a disease mutation, and Arg442 is replaced by glutamine in some animal species with dichromatic or monochromatic vision. These and other unique structural features and the disease link conferred by CNGB3 indicate a critical role of CNGB3 in shaping cone photoresponses.

PubMed: 34969976
DOI: 10.1038/s41594-021-00699-y

Experimental method

ELECTRON MICROSCOPY (2.93 Å)