The Cryo-EM structure of the CorA channel from Methanocaldococcus jannaschii in low magnesium conditions.
Biochim Biophys Acta
; 1848(10 Pt A): 2206-15, 2015 Oct.
Article
em En
| MEDLINE
| ID: mdl-26051127
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.
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MEDLINE
Assunto principal:
Modelos Moleculares
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Proteínas de Escherichia coli
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Proteínas de Transporte de Cátions
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Methanocaldococcus
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Magnésio
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article