5V4S

CryoEM Structure of a Prokaryotic Cyclic Nucleotide-Gated Ion Channel

Summary for 5V4S

• Entry DOI: 10.2210/pdb5v4s/pdb
• EMDB information: 8632 8633
• Descriptor: Transporter, cation channel family / cyclic nucleotide-binding domain multi-domain protein (1 entity in total)
• Functional Keywords: ion channel, cyclic nucleotide, allostery, vision, olfaction, transport protein
• Biological source: Leptospira licerasiae serovar Varillal str. VAR 010
• Total number of polymer chains: 4
• Total formula weight: 213859.14

Authors

James, Z.M.,Borst, A.J.,Haitin, Y.,Frenz, B.,DiMaio, F.,Zagotta, W.N.,Veesler, D. (deposition date: 2017-03-10, release date: 2017-04-12, Last modification date: 2024-03-13)

Primary citation

James, Z.M.,Borst, A.J.,Haitin, Y.,Frenz, B.,DiMaio, F.,Zagotta, W.N.,Veesler, D.
CryoEM structure of a prokaryotic cyclic nucleotide-gated ion channel.
Proc. Natl. Acad. Sci. U.S.A., 114:4430-4435, 2017

PubMed Abstract: Cyclic nucleotide-gated (CNG) and hyperpolarization-activated cyclic nucleotide-regulated (HCN) ion channels play crucial physiological roles in phototransduction, olfaction, and cardiac pace making. These channels are characterized by the presence of a carboxyl-terminal cyclic nucleotide-binding domain (CNBD) that connects to the channel pore via a C-linker domain. Although cyclic nucleotide binding has been shown to promote CNG and HCN channel opening, the precise mechanism underlying gating remains poorly understood. Here we used cryoEM to determine the structure of the intact LliK CNG channel isolated from -which shares sequence similarity to eukaryotic CNG and HCN channels-in the presence of a saturating concentration of cAMP. A short S4-S5 linker connects nearby voltage-sensing and pore domains to produce a non-domain-swapped transmembrane architecture, which appears to be a hallmark of this channel family. We also observe major conformational changes of the LliK C-linkers and CNBDs relative to the crystal structures of isolated C-linker/CNBD fragments and the cryoEM structures of related CNG, HCN, and KCNH channels. The conformation of our LliK structure may represent a functional state of this channel family not captured in previous studies.

PubMed: 28396445
DOI: 10.1073/pnas.1700248114

Experimental method

ELECTRON MICROSCOPY (4.2 Å)