1JRX

Crystal structure of Arg402Ala mutant flavocytochrome c3 from Shewanella frigidimarina


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.186 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Kinetic and crystallographic analysis of the key active site acid/base arginine in a soluble fumarate reductase.

Mowat, C.G.Moysey, R.Miles, C.S.Leys, D.Doherty, M.K.Taylor, P.Walkinshaw, M.D.Reid, G.A.Chapman, S.K.

(2001) Biochemistry 40: 12292-12298

  • Primary Citation of Related Structures:  1JRY, 1JRZ

  • PubMed Abstract: 
  • There is now overwhelming evidence supporting a common mechanism for fumarate reduction in the respiratory fumarate reductases. The X-ray structures of substrate-bound forms of these enzymes indicate that the substrate is well positioned to accept a ...

    There is now overwhelming evidence supporting a common mechanism for fumarate reduction in the respiratory fumarate reductases. The X-ray structures of substrate-bound forms of these enzymes indicate that the substrate is well positioned to accept a hydride from FAD and a proton from an arginine side chain. Recent work on the enzyme from Shewanella frigidimarina [Doherty, M. K., Pealing, S. L., Miles, C. S., Moysey, R., Taylor, P., Walkinshaw, M. D., Reid, G. A., and Chapman, S. K. (2000) Biochemistry 39, 10695-10701] has strengthened the assignment of an arginine (Arg402) as the proton donor in fumarate reduction. Here we describe the crystallographic and kinetic analyses of the R402A, R402K, and R402Y mutant forms of the Shewanella enzyme. The crystal structure of the R402A mutant (2.0 A resolution) shows it to be virtually identical to the wild-type enzyme, apart from the fact that a water molecule occupies the position previously taken by part of the guanidine group of R402. Although structurally similar to the wild-type enzyme, the R402A mutant is inactive under all the conditions that were studied. This implies that a water molecule, in this position in the active site, cannot function as the proton donor for fumarate reduction. In contrast to the R402A mutation, both the R402K and R402Y mutant enzymes are active. Although this activity was at a very low level (at pH 7.2 some 10(4)-fold lower than that for the wild type), it does imply that both lysine and tyrosine can fulfill the role of an active site proton donor, albeit very poorly. The crystal structures of the R402K and R402Y mutant enzymes (2.0 A resolution) show that distances from the lysine and tyrosine side chains to the nearest carbon atom of fumarate are approximately 3.5 A, clearly permitting proton transfer. The combined results from mutagenesis, crystallographic, and kinetic studies provide formidable evidence that R402 acts as both a Lewis acid (stabilizing the build-up of negative charge upon hydride transfer from FAD to fumarate) and a Brønsted acid (donating the proton to the substrate to complete the formation of succinate).


    Organizational Affiliation

    Department of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
FLAVOCYTOCHROME C
A, B
571Shewanella frigidimarinaGene Names: fccA (fcc3)
EC: 1.3.5.4
Find proteins for P0C278 (Shewanella frigidimarina)
Go to UniProtKB:  P0C278
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A, B
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
FAD
Query on FAD

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Download CCD File 
A, B
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
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
FUM
Query on FUM

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Download CCD File 
A, B
FUMARIC ACID
C4 H4 O4
VZCYOOQTPOCHFL-OWOJBTEDSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.186 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 75.966α = 90.00
b = 85.930β = 104.74
c = 88.320γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
AMoREphasing
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-11-02
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance