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The Cryo-EM structure of the CorA channel from Methanocaldococcus jannaschii in low magnesium conditions

DOI: 10.1016/j.bbamem.2015.06.002 DOI Help

Authors: Robert Cleverley (University of Manchester) , James Kean (University of Manchester) , Chitra Shintre (University of Oxford) , Clair Baldock (University of Manchester) , Jeremy Derrick (The University of Manchester) , Robert C. Ford (University of Manchester) , Stephen Prince (University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochimica Et Biophysica Acta (bba) - Biomembranes

State: Published (Approved)
Published: June 2015
Diamond Proposal Number(s): 1023 , 1050

Open Access Open Access

Abstract: CorA channels are responsible for the uptake of essential magnesium ions by bacteria. X-ray crystal structures have been resolved for two full-length CorA channels, each in a non-conducting state with magnesium ions bound to the protein: These structures reveal a homo-pentameric quaternary structure with approximate 5-fold rotational symmetry about a central pore axis. We report the structure of the detergent solubilized Methanocaldococcus jannaschii CorA channel determined by Cryo-Electron Microscopy and Single Particle Averaging, supported by Small Angle X-ray Scattering and X-ray crystallography. This structure also shows a pentameric channel but with a highly asymmetric domain structure. The asymmetry of the domains includes differential separations between the trans-membrane segments, which reflects mechanical coupling of the cytoplasmic domain to the trans-membrane domain. This structure therefore reveals an important aspect of the gating mechanism of CorA channels by providing an indication of how the absence of magnesium ions leads to major structural changes.

Journal Keywords: Ion Channel; Channel Gating; Cryo-Electron Microscopy; Membrane Protein

Subject Areas: Biology and Bio-materials, Chemistry

Diamond Offline Facilities: Membrane Protein Laboratory (MPL)
Instruments: I22-Small angle scattering & Diffraction , I24-Microfocus Macromolecular Crystallography

Added On: 14/06/2015 19:57


Discipline Tags:

Biochemistry Chemistry Structural biology Biophysics Life Sciences & Biotech

Technical Tags:

Diffraction Scattering Macromolecular Crystallography (MX) Small Angle X-ray Scattering (SAXS)