4CHV

The electron crystallography structure of the cAMP-bound potassium channel MloK1

Summary for 4CHV

• Entry DOI: 10.2210/pdb4chv/pdb
• Related: 4CHW
• EMDB information: 2526
• Descriptor: CYCLIC NUCLEOTIDE-GATED POTASSIUM CHANNEL MLL3241, POTASSIUM ION (2 entities in total)
• Functional Keywords: transport, 2dx, voltage gated potassium channel, cnbd, 2d crystal
• Biological source: MESORHIZOBIUM LOTI
• Total number of polymer chains: 4
• Total formula weight: 154458.85

Authors

Kowal, J.,Chami, M.,Baumgartner, P.,Arheit, M.,Chiu, P.L.,Rangl, M.,Scheuring, S.,Schroeder, G.F.,Nimigean, C.M.,Stahlberg, H. (deposition date: 2013-12-04, release date: 2014-01-15, Last modification date: 2024-05-08)

Primary citation

Kowal, J.,Chami, M.,Baumgartner, P.,Arheit, M.,Chiu, P.L.,Rangl, M.,Scheuring, S.,Schroeder, G.F.,Nimigean, C.M.,Stahlberg, H.
Ligand-Induced Structural Changes in the Cyclic Nucleotide-Modulated Potassium Channel Mlok1
Nat.Commun., 5:3106-, 2014

PubMed Abstract: Cyclic nucleotide-modulated ion channels are important for signal transduction and pacemaking in eukaryotes. The molecular determinants of ligand gating in these channels are still unknown, mainly because of a lack of direct structural information. Here we report ligand-induced conformational changes in full-length MloK1, a cyclic nucleotide-modulated potassium channel from the bacterium Mesorhizobium loti, analysed by electron crystallography and atomic force microscopy. Upon cAMP binding, the cyclic nucleotide-binding domains move vertically towards the membrane, and directly contact the S1-S4 voltage sensor domains. This is accompanied by a significant shift and tilt of the voltage sensor domain helices. In both states, the inner pore-lining helices are in an 'open' conformation. We propose a mechanism in which ligand binding can favour pore opening via a direct interaction between the cyclic nucleotide-binding domains and voltage sensors. This offers a simple mechanistic hypothesis for the coupling between ligand gating and voltage sensing in eukaryotic HCN channels.

PubMed: 24469021
DOI: 10.1038/NCOMMS4106

Experimental method

ELECTRON CRYSTALLOGRAPHY (7 Å)