Cytochrome b5 of Ostreococcus tauri virus 2

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.191 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report

Ligand Structure Quality Assessment 

This is version 1.2 of the entry. See complete history


Functional and Structural Characterisation of a Viral Cytochrome B5.

Reid, E.L.Weynberg, K.D.Love, J.Isupov, M.N.Littlechild, J.A.Wilson, W.H.Kelly, S.L.Lamb, D.C.Allen, M.J.

(2013) FEBS Lett 587: 3633

  • DOI: https://doi.org/10.1016/j.febslet.2013.09.035
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Cytochrome b5 is a ubiquitous electron transport protein. The sequenced viral OtV-2 genome, which infects Ostreococcus tauri, was predicted to encode a putative cytochrome b5 enzyme. Using purified OtV-2 cytochrome b5 we confirm this protein has identical spectral properties to purified human cytochrome b5 and additionally that the viral enzyme can substitute for yeast cytochrome b5 in yeast cytochrome P450 51 mediated sterol 14α-demethylation. The crystal structure of the OtV-2 cytochrome b5 enzyme reveals a single domain, comprising four β sheets, four α helices and a haem moiety, which is similar to that found in larger eukaryotic cytochrome proteins. As a product of a horizontal gene transfer event involving a subdomain of the host fumarate reductase-like protein, OtV-2 cytochrome b5 appears to have diverged in function and is likely to have evolved an entirely new role for the virus during infection. Indeed, lacking a hydrophobic C-terminal anchor, OtV-2 encodes the first cytosolic cytochrome b5 characterised. The lack of requirement for membrane attachment (in contrast to all other microsomal cytochrome b5s) may be a reflection of the small size of the host cell, further emphasizes the unique nature of this virus gene product and draws attention to the potential importance of cytochrome b5 metabolic activity at the extremes of cellular scale.

  • Organizational Affiliation

    Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK; Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D
91Ostreococcus tauri virus 2Mutation(s): 0 
Find proteins for E4WM77 (Ostreococcus tauri virus 2)
Explore E4WM77 
Go to UniProtKB:  E4WM77
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE4WM77
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.191 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.69α = 90
b = 58.5β = 90
c = 127.07γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-09-04
    Type: Initial release
  • Version 1.1: 2014-04-23
    Changes: Database references
  • Version 1.2: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description