2FY8

Crystal structure of MthK rck domain in its ligand-free gating-ring form

Summary for 2FY8

• Entry DOI: 10.2210/pdb2fy8/pdb
• Related: 1LNQ 2AEF 2AEJ 2AEM
• Descriptor: Calcium-gated potassium channel mthK (2 entities in total)
• Functional Keywords: transport, ionic channel, alternative initiation, transmembrane, ion transport, potassium, potassium transport, membrane, gating ring, closed conformation, partially open conformation, transition state, transport protein
• Biological source: Methanothermobacter thermautotrophicus
• Cellular location: Cell membrane; Multi-pass membrane protein: O27564
• Total number of polymer chains: 8
• Total formula weight: 203576.00

Authors

Ye, S.,Jiang, Y. (deposition date: 2006-02-07, release date: 2006-09-05, Last modification date: 2023-08-30)

Primary citation

Ye, S.,Li, Y.,Chen, L.,Jiang, Y.
Crystal Structures of a Ligand-free MthK Gating Ring: Insights into the Ligand Gating Mechanism of K(+) Channels.
Cell(Cambridge,Mass.), 126:1161-1173, 2006

PubMed Abstract: MthK is a prokaryotic Ca(2+)-gated K(+) channel that, like other ligand-gated channels, converts the chemical energy of ligand binding to the mechanical force of channel opening. The channel's eight ligand-binding domains, the RCK domains, form an octameric gating ring in which Ca(2+) binding induces conformational changes that open the channel. Here we present the crystal structures of the MthK gating ring in closed and partially open states at 2.8 A, both obtained from the same crystal grown in the absence of Ca(2+). Furthermore, our biochemical and electrophysiological analyses demonstrate that MthK is regulated by both Ca(2+) and pH. Ca(2+) regulates the channel by changing the equilibrium of the gating ring between closed and open states, while pH regulates channel gating by affecting gating-ring stability. Our findings, along with the previously determined open MthK structure, allow us to elucidate the ligand gating mechanism of RCK-regulated K(+) channels.

PubMed: 16990139
DOI: 10.1016/j.cell.2006.08.029

Experimental method

X-RAY DIFFRACTION (2.79 Å)