1YX3

NMR structure of Allochromatium vinosum DsrC: Northeast Structural Genomics Consortium target OP4


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 25 
  • Conformers Submitted: 20 
  • Selection Criteria: low energy structures with fewest restraint violations 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Allochromatium vinosum DsrC: solution-state NMR structure, redox properties, and interaction with DsrEFH, a protein essential for purple sulfur bacterial sulfur oxidation.

Cort, J.R.Selan, U.Schulte, A.Grimm, F.Kennedy, M.A.Dahl, C.

(2008) J.Mol.Biol. 382: 692-707

  • DOI: 10.1016/j.jmb.2008.07.022

  • PubMed Abstract: 
  • Sequenced genomes of dissimilatory sulfur-oxidizing and sulfate-reducing bacteria containing genes coding for DsrAB, the enzyme dissimilatory sulfite reductase, inevitably also contain the gene coding for the 12-kDa DsrC protein. DsrC is thought to h ...

    Sequenced genomes of dissimilatory sulfur-oxidizing and sulfate-reducing bacteria containing genes coding for DsrAB, the enzyme dissimilatory sulfite reductase, inevitably also contain the gene coding for the 12-kDa DsrC protein. DsrC is thought to have a yet unidentified role associated with the activity of DsrAB. Here we report the solution structure of DsrC from the sulfur-oxidizing purple sulfur bacterium Allochromatium vinosum determined with NMR spectroscopy in reducing conditions, and we describe the redox behavior of two conserved cysteine residues upon transfer to an oxidizing environment. In reducing conditions, the DsrC structure is disordered in the highly conserved carboxy-terminus. We present multiple lines of evidence that, in oxidizing conditions, a strictly conserved cysteine (Cys111) at the penultimate position in the sequence forms an intramolecular disulfide bond with Cys100, which is conserved in DsrC in all organisms with DsrAB. While an intermolecular Cys111-Cys111 disulfide-bonded dimer is rapidly formed under oxidizing conditions, the intramolecularly disulfide-bonded species (Cys100-Cys111) is the thermodynamically stable form of the protein under these conditions. Treatment of the disulfidic forms with reducing agent regenerates the monomeric species that was structurally characterized. Using a band-shift technique under nondenaturing conditions, we obtained evidence for the interaction of DsrC with heterohexameric DsrEFH, a protein encoded in the same operon. Mutation of Cys100 to serine prevented formation of the DsrC species assigned as an intramolecular disulfide in oxidizing conditions, while still allowing formation of the intermolecular Cys111-Cys111 dimer. In the reduced form, this mutant protein still interacted with DsrEFH. This was not the case for the Cys111Ser and Cys100Ser/Cys111Ser mutants, both of which also did not form protein dimers. Our observations highlight the central importance of the carboxy-terminal DsrC cysteine residues and are consistent with a role as a sulfur-substrate binding/transferring protein, as well as with an electron-transfer function via thiol-disulfide interchanges.


    Related Citations: 
    • Novel genes of the dsr gene cluster and evidence for close interaction of Dsr proteins during sulfur oxidation in the phototrophic sulfur bacterium Allochromatium vinosum.
      Dahl, C.,Engels, S.,Pott-Sperling, A.S.,Schulte, A.,Sander, J.,Lubbe, Y.,Deuster, O.,Brune, D.C.
      (2005) J.Bacteriol. 187: 1392
    • Sirohaem sulfite reductase and other proteins encoded by genes at the dsr locus of Chromatium vinosum are involved in the oxidation of intracellular sulfur.
      Pott, A.S.,Dahl, C.
      (1998) MICROBIOLOGY 144: 1881


    Organizational Affiliation

    Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
hypothetical protein DsrC
A
132Allochromatium vinosumMutation(s): 0 
Gene Names: dsrC
EC: 2.8.1.-
Find proteins for O87899 (Allochromatium vinosum)
Go to UniProtKB:  O87899
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 25 
  • Conformers Submitted: 20 
  • Selection Criteria: low energy structures with fewest restraint violations 
  • Olderado: 1YX3 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-04-19
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance