1LS9

Structure of the Cytochrome c6 from the Green Alga Cladophora glomerata


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.3 Å
  • R-Value Free: 0.190 
  • R-Value Work: 0.143 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Basis for the Molecular Properties of Cytochrome C(6)

Dikiy, A.Carpentier, W.Vandenberghe, I.Borsari, M.Safarov, N.Dikaya, E.Van Beeumen, J.Ciurli, S.

(2002) Biochemistry 41: 14689-14699


  • PubMed Abstract: 
  • This is a thorough biochemical, spectroscopic, electrochemical, and structural study of a cytochrome c(6) isolated from the filamentous green alga Cladophora glomerata. The protein sequence, elucidated using chemical and mass spectrometric techniques ...

    This is a thorough biochemical, spectroscopic, electrochemical, and structural study of a cytochrome c(6) isolated from the filamentous green alga Cladophora glomerata. The protein sequence, elucidated using chemical and mass spectrometric techniques, features 91 amino acids and the characteristic CXXCH heme-binding motif found in c-type cytochromes. The protein is monomeric in both oxidation forms, thereby putting in question a functional role for protein dimerization. Direct electrochemical measurements established, for the first time, the kinetic and thermodynamic data for the redox process in a cytochrome c(6). In particular, the quasi-reversible and diffusion-controlled redox process is accompanied by negative enthalpy and entropy changes, resulting in an E degrees ' value of 0.352 V at 298 K. The pH-dependent properties of the oxidized protein, detected by UV-visible, NMR, and direct cyclic voltammetry, indicate the presence of two acid-base equilibria occurring in the acidic (pK(a) = 4.5) and alkaline regions (pK(a) = 9.0). NMR and electronic spectra allowed the assignment of these equilibria to deprotonation of heme propionate-7 and to replacement of the axial methionine with another ligand, respectively. The 1.3 A resolution X-ray structure of the oxidized protein, revealing a fold typical for class I cytochromes, suggests that the conserved Lys60 replaces the axial methionine at pH >9. The heme solvent accessibility is low, and no water molecules were found in the vicinity of the axial ligands of the heme Fe. A structure-based alignment of cytochromes c(6), and the direct comparison of their structures, indicate a substantial degree of identity between the tertiary structures and suggest patches involved in protein-protein interaction. In particular, the surface electrostatic potential of cytochromes c(6) features a hydrophobic region around the heme cofactor, and a backside surface rich in negative charges.


    Organizational Affiliation

    Department of Agro-Environmental Science and Technology, University of Bologna, Via Filippo Re 8, Italy.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CYTOCHROME C6
A
91Cladophora glomerataMutation(s): 0 
Gene Names: petJ
Find proteins for P83391 (Cladophora glomerata)
Go to UniProtKB:  P83391
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.3 Å
  • R-Value Free: 0.190 
  • R-Value Work: 0.143 
  • Space Group: P 41 21 2
Unit Cell:
Length (Å)Angle (°)
a = 46.063α = 90.00
b = 46.063β = 90.00
c = 100.526γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
AMoREphasing
DENZOdata reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2002-05-17 
  • Released Date: 2002-12-25 
  • Deposition Author(s): Carpentier, W.

Revision History 

  • Version 1.0: 2002-12-25
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance