1EUE

RAT OUTER MITOCHONDRIAL MEMBRANE CYTOCHROME B5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.197 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Modulation of redox potential in electron transfer proteins: effects of complex formation on the active site microenvironment of cytochrome b5.

Wirtz, M.Oganesyan, V.Zhang, X.Studer, J.Rivera, M.

(2001) FARADAY DISC.CHEM.SOC 116: 221-234


  • PubMed Abstract: 
  • The reduction potential of cytochrome b5 is modulated via the formation of a complex with polylysine at the electrode surface (Rivera et al., Biochemistry, 1998, 37, 1485). This modulation is thought to originate from the neutralization of a solvent ...

    The reduction potential of cytochrome b5 is modulated via the formation of a complex with polylysine at the electrode surface (Rivera et al., Biochemistry, 1998, 37, 1485). This modulation is thought to originate from the neutralization of a solvent exposed heme propionate and from dehydration of the complex interface. Although direct evidence demonstrating that neutralization of the charge on the heme propionate contributes to the modulation of the redox potential of cytochrome b5 has been obtained, evidence demonstrating that water exclusion from the complex interface plays a similar role has not been conclusive. Herein we report the preparation of the V45I/V61I double mutant of rat liver outer mitochondrial membrane (OM) cytochrome b5. This mutant has been engineered with the aim of restricting water accessibility to the exposed heme edge of cytochrome b5. The X-ray crystal structure of the V45I/V61I mutant revealed that the side chain of Ile at positions 45 and 61 restricts water accessibility to the interior of the heme cavity and protects a large section of the heme edge from the aqueous environment. Electrochemical studies performed with the V45I/V61I mutant of cytochrome b5, and with a derivative in which the heme propionates have been converted into the corresponding dimethyl ester groups, clearly demonstrate that dehydration of the heme edge contributes to the modulation of the reduction potential of cytochrome b5. In fact, these studies showed that exclusion of water from the complex interface exerts an effect (approximately 40 mV shift) that is comparable, if not larger, than the one originating from neutralization of the charge on the solvent exposed heme propionate (approximately 30 mV shift).


    Organizational Affiliation

    Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CYTOCHROME B5
A, B
86Rattus norvegicusMutation(s): 2 
Gene Names: Cyb5b (Cyb5m, Omb5)
Find proteins for P04166 (Rattus norvegicus)
Go to UniProtKB:  P04166
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
A, B
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: 1.8 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.197 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 46.230α = 90.00
b = 70.770β = 90.00
c = 72.440γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
CNSphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-04-04
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2014-02-19
    Type: Database references
  • Version 1.4: 2017-10-04
    Type: Refinement description