PDBsum entry 2n4x

Membrane protein

PDB id: 2n4x

Contents

Protein chain

192 a.a.

PDB id:

2n4x

Name:

Membrane protein

Title:

Structure of the transmembrane electron transporter ccda

Structure:

CytochromE C-type biogenesis protein (ccda). Chain: a. Engineered: yes. Mutation: yes

Source:

Archaeoglobus fulgidus dsm 4304. Organism_taxid: 224325. Strain: atcc 49558 / vc-16 / dsm 4304 / jcm 9628 / nbrc 100126. Gene: af_1057. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

15 models

Authors:

J.J.Chou,J.A.Williamson

Key ref:

J.A.Williamson et al. (2015). Structure and multistate function of the transmembrane electron transporter CcdA. Nat Struct Biol, 22, 809-814. PubMed id: 26389738 DOI: 10.1038/nsmb.3099

Date:

01-Jul-15 Release date: 18-May-16

Protein chain

O29205  (O29205_ARCFU) -  Cytochrome C-type biogenesis protein (CcdA) from Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16)

Seq: 190 a.a.

Struc: 192 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1038/nsmb.3099

Nat Struct Biol 22:809-814 (2015)

PubMed id: 26389738

Structure and multistate function of the transmembrane electron transporter CcdA.

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

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.