Nostoc sp Cytochrome c6

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.181 

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The dynamic complex of cytochrome c6 and cytochrome f studied with paramagnetic NMR spectroscopy

Diaz-Moreno, I.Hulsker, R.Skubak, P.Foerster, J.M.Cavazzini, D.Finiguerra, M.G.Diaz-Quintana, A.Moreno-Beltran, B.Rossi, G.L.Ullmann, G.M.Pannu, N.S.De la Rosa, M.A.Ubbink, M.

(2014) Biochim Biophys Acta 1837: 1305-1315

  • DOI: https://doi.org/10.1016/j.bbabio.2014.03.009
  • Primary Citation of Related Structures:  
    4GYD, 4H0J, 4H0K

  • PubMed Abstract: 

    The rapid transfer of electrons in the photosynthetic redox chain is achieved by the formation of short-lived complexes of cytochrome b6f with the electron transfer proteins plastocyanin and cytochrome c6. A balance must exist between fast intermolecular electron transfer and rapid dissociation, which requires the formation of a complex that has limited specificity. The interaction of the soluble fragment of cytochrome f and cytochrome c6 from the cyanobacterium Nostoc sp. PCC 7119 was studied using NMR spectroscopy and X-ray diffraction. The crystal structures of wild type, M58H and M58C cytochrome c6 were determined. The M58C variant is an excellent low potential mimic of the wild type protein and was used in chemical shift perturbation and paramagnetic relaxation NMR experiments to characterize the complex with cytochrome f. The interaction is highly dynamic and can be described as a pure encounter complex, with no dominant stereospecific complex. Ensemble docking calculations and Monte-Carlo simulations suggest a model in which charge-charge interactions pre-orient cytochrome c6 with its haem edge toward cytochrome f to form an ensemble of orientations with extensive contacts between the hydrophobic patches on both cytochromes, bringing the two haem groups sufficiently close to allow for rapid electron transfer. This model of complex formation allows for a gradual increase and decrease of the hydrophobic interactions during association and dissociation, thus avoiding a high transition state barrier that would slow down the dissociation process.

  • Organizational Affiliation

    Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain. Electronic address: idiazmoreno@us.es.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytochrome c6
A, B, C, D, E
A, B, C, D, E, F
86Nostoc sp. PCC 7120 = FACHB-418Mutation(s): 0 
Gene Names: petJ
Find proteins for P0A3X7 (Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576))
Explore P0A3X7 
Go to UniProtKB:  P0A3X7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A3X7
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.181 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.721α = 90
b = 79.803β = 90
c = 80.154γ = 90
Software Package:
Software NamePurpose
DNAdata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-09-11
    Type: Initial release
  • Version 1.1: 2017-01-25
    Changes: Database references
  • Version 2.0: 2019-10-02
    Changes: Atomic model, Data collection, Derived calculations, Non-polymer description, Structure summary