Structure of the Transmembrane Electron Transporter CcdA

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 75 
  • Conformers Submitted: 15 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation   3D Report Full Report

This is version 1.2 of the entry. See complete history


Structure and multistate function of the transmembrane electron transporter CcdA.

Williamson, J.A.Cho, S.H.Ye, J.Collet, J.F.Beckwith, J.R.Chou, J.J.

(2015) Nat Struct Mol Biol 22: 809-814

  • DOI: https://doi.org/10.1038/nsmb.3099
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The mechanism by which transmembrane reductases use a single pair of cysteine residues to relay electrons between protein substrates across biological membranes is a long-standing mystery in thiol-redox biochemistry. Here we show the NMR structure of a reduced-state mimic of archaeal CcdA, a protein that transfers electrons across the inner membrane, by using a redox-active NMR sample. The two cysteine positions in CcdA are separated by 20 Å. Whereas one is accessible to the cytoplasm, the other resides in the protein core, thus implying that conformational exchange is required for periplasmic accessibility. In vivo mixed disulfide-trapping experiments validated the functional positioning of the cysteines, and in vitro accessibility results confirmed conformational exchange. Our NMR and functional data together show the existence of multiple conformational states and suggest a four-state model for relaying electrons from cytosolic to periplasmic redox substrates.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytochrome C-type biogenesis protein (CcdA)208Archaeoglobus fulgidus DSM 4304Mutation(s): 2 
Gene Names: AF_1057
Membrane Entity: Yes 
Find proteins for O29205 (Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16))
Explore O29205 
Go to UniProtKB:  O29205
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO29205
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 75 
  • Conformers Submitted: 15 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-05-18
    Type: Initial release
  • Version 1.1: 2023-06-14
    Changes: Data collection, Database references, Other
  • Version 1.2: 2024-05-15
    Changes: Data collection, Database references