2FY8: Crystal Structure Of Mthk Rck Domain In Its Ligand-Free Gating-Ring Form

Citation:
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.
PDB ID: 2FY8Download
MMDB ID: 40867
PDB Deposition Date: 2006/2/7
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 2.79  Å
Source Organism:
Similar Structures:
Biological Unit for 2FY8: octameric; determined by author
Molecular Components in 2FY8
Label Count Molecule
Proteins (8 molecules)
8
Calcium-gated Potassium Channel Mthk(Gene symbol: MTH_RS07260)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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