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Title | Cryo-EM structures of fungal and metazoan mitochondrial calcium uniporters. |
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Journal, issue, pages | Nature, Vol. 559, Issue 7715, Page 580-584, Year 2018 |
Publish date | Jul 11, 2018 |
Authors | Rozbeh Baradaran / Chongyuan Wang / Andrew Francis Siliciano / Stephen Barstow Long / |
PubMed Abstract | The mitochondrial calcium uniporter (MCU) is a highly selective calcium channel and a major route of calcium entry into mitochondria. How the channel catalyses ion permeation and achieves ...The mitochondrial calcium uniporter (MCU) is a highly selective calcium channel and a major route of calcium entry into mitochondria. How the channel catalyses ion permeation and achieves ion selectivity are not well understood, partly because MCU is thought to have a distinct architecture in comparison to other cellular channels. Here we report cryo-electron microscopy reconstructions of MCU channels from zebrafish and Cyphellophora europaea at 8.5 Å and 3.2 Å resolutions, respectively. In contrast to a previous report of pentameric stoichiometry for MCU, both channels are tetramers. The atomic model of C. europaea MCU shows that a conserved WDXXEP signature sequence forms the selectivity filter, in which calcium ions are arranged in single file. Coiled-coil legs connect the pore to N-terminal domains in the mitochondrial matrix. In C. europaea MCU, the N-terminal domains assemble as a dimer of dimers; in zebrafish MCU, they form an asymmetric crescent. The structures define principles that underlie ion permeation and calcium selectivity in this unusual channel. |
External links | Nature / PubMed:29995857 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.2 - 8.5 Å |
Structure data | EMDB-7971: cryo-EM structure of the mitochondrial calcium uniporter MCU from the fungus Cyphellophora europaea EMDB-7972: |
Chemicals | ChemComp-DGG: ChemComp-CA: |
Source |
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Keywords | MEMBRANE PROTEIN / mitochondria / calcium / ion channel / eukaryotic |