Characterization of the malformed, recombinant cytochrome rC552

Experimental Data Snapshot

  • Resolution: 1.40 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.197 

wwPDB Validation   3D Report Full Report

Ligand Structure Quality Assessment 

This is version 1.2 of the entry. See complete history


Cytochrome rC552, formed during expression of the truncated, Thermus thermophilus cytochrome c552 gene in the cytoplasm of Escherichia coli, reacts spontaneously to form protein-bound 2-formyl-4-vinyl (Spirographis) heme.

Fee, J.A.Todaro, T.R.Luna, E.Sanders, D.Hunsicker-Wang, L.M.Patel, K.M.Bren, K.L.Gomez-Moran, E.Hill, M.G.Ai, J.Loehr, T.M.Oertling, W.A.Williams, P.A.Stout, C.D.McRee, D.Pastuszyn, A.

(2004) Biochemistry 43: 12162-12176

  • DOI: https://doi.org/10.1021/bi048968l
  • Primary Citation of Related Structures:  
    1QYZ, 1R0Q

  • PubMed Abstract: 

    Expression of the truncated (lacking an N-terminal signal sequence) structural gene of Thermus thermophilus cytochrome c(552) in the cytoplasm of Escherichia coli yields both dimeric (rC(557)) and monomeric (rC(552)) cytochrome c-like proteins [Keightley, J. A., et al. (1998) J. Biol. Chem. 273, 12006-12016], which form spontaneously without the involvement of cytochrome c maturation factors. Cytochrome rC(557) is comprised of a dimer and has been structurally characterized [McRee, D., et al. (2001) J. Biol. Chem. 276, 6537-6544]. Unexpectedly, the monomeric rC(552) transforms spontaneously to a cytochrome-like chromophore having, in its reduced state, the Q(oo) transition (alpha-band) at 572 nm (therefore called p572). The X-ray crystallographic structure of rC(552), at 1.41 A resolution, shows that the 2-vinyl group of heme ring I is converted to a [heme-CO-CH(2)-S-CH(2)-C(alpha)] conjugate with cysteine 11. Electron density maps obtained from isomorphous crystals of p572 at 1.61 A resolution reveal that the 2-vinyl group has been oxidized to a formyl group. This explains the lower energy of the Q(oo)() transition, the presence of a new, high-frequency band in the resonance Raman spectra at 1666 cm(-1) for oxidized and at 1646 cm(-1) for reduced samples, and the greatly altered, paramagnetically shifted (1)H NMR spectrum observed for this species. The overall process defines a novel mechanism for oxidation of the 2-vinyl group to a 2-formyl group and adds to the surprising array of chemical reactions that occur in the interaction of heme with the CXXCH sequence motif in apocytochromes c.

  • Organizational Affiliation

    Department of Biology, University of California at San Diego, La Jolla, California 92093, USA. jafee@scripps.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytochrome c-552131Thermus thermophilusMutation(s): 0 
Gene Names: CYCA
Find proteins for P04164 (Thermus thermophilus)
Explore P04164 
Go to UniProtKB:  P04164
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04164
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HCO

Download Ideal Coordinates CCD File 
C34 H34 Fe N4 O5
Experimental Data & Validation

Experimental Data

  • Resolution: 1.40 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.197 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 87.463α = 90
b = 87.463β = 90
c = 32.209γ = 120
Software Package:
Software NamePurpose
SHELXmodel building
MOSFLMdata reduction
CCP4data scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2004-09-28
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance