5ID3

Solution structure of the pore-forming region of C. elegans Mitochondrial Calcium Uniporter (MCU)


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 150 
  • Conformers Submitted: 15 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Architecture of the mitochondrial calcium uniporter.

Oxenoid, K.Dong, Y.Cao, C.Cui, T.Sancak, Y.Markhard, A.L.Grabarek, Z.Kong, L.Liu, Z.Ouyang, B.Cong, Y.Mootha, V.K.Chou, J.J.

(2016) Nature 533: 269-273

  • DOI: 10.1038/nature17656

  • PubMed Abstract: 
  • Mitochondria from many eukaryotic clades take up large amounts of calcium (Ca(2+)) via an inner membrane transporter called the uniporter. Transport by the uniporter is membrane potential dependent and sensitive to ruthenium red or its derivative Ru3 ...

    Mitochondria from many eukaryotic clades take up large amounts of calcium (Ca(2+)) via an inner membrane transporter called the uniporter. Transport by the uniporter is membrane potential dependent and sensitive to ruthenium red or its derivative Ru360 (ref. 1). Electrophysiological studies have shown that the uniporter is an ion channel with remarkably high conductance and selectivity. Ca(2+) entry into mitochondria is also known to activate the tricarboxylic acid cycle and seems to be crucial for matching the production of ATP in mitochondria with its cytosolic demand. Mitochondrial calcium uniporter (MCU) is the pore-forming and Ca(2+)-conducting subunit of the uniporter holocomplex, but its primary sequence does not resemble any calcium channel studied to date. Here we report the structure of the pore domain of MCU from Caenorhabditis elegans, determined using nuclear magnetic resonance (NMR) and electron microscopy (EM). MCU is a homo-oligomer in which the second transmembrane helix forms a hydrophilic pore across the membrane. The channel assembly represents a new solution of ion channel architecture, and is stabilized by a coiled-coil motif protruding into the mitochondrial matrix. The critical DXXE motif forms the pore entrance, which features two carboxylate rings; based on the ring dimensions and functional mutagenesis, these rings appear to form the selectivity filter. To our knowledge, this is one of the largest membrane protein structures characterized by NMR, and provides a structural blueprint for understanding the function of this channel.


    Organizational Affiliation

    Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Mitochondrial Calcium Uniporter
A, B, C, D, E
159Caenorhabditis elegansMutation(s): 8 
Gene Names: mcu-1
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Calcium Ion-Selective
Protein: 
Mitochondrial calcium uniporter
Find proteins for Q21121 (Caenorhabditis elegans)
Go to UniProtKB:  Q21121
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 150 
  • Conformers Submitted: 15 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited StatesGM094608
CASChinaXDB08030301

Revision History 

  • Version 1.0: 2016-05-04
    Type: Initial release
  • Version 1.1: 2016-05-18
    Type: Database references
  • Version 1.2: 2016-05-25
    Type: Database references
  • Version 1.3: 2017-09-27
    Type: Author supporting evidence, Database references, Structure summary