1QLT

STRUCTURE OF THE H422A MUTANT OF THE FLAVOENZYME VANILLYL-ALCOHOL OXIDASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.210 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Covalent Flavinylation is Essential for Efficient Redox Catalysis in Vanillyl-Alcohol Oxidase.

Fraaije, M.W.Van Den Heuvel, R.H.H.Van Berkel, W.J.H.Mattevi, A.

(2000) J.Biol.Chem. 274: 35514

  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • By mutating the target residue of covalent flavinylation in vanillyl-alcohol oxidase, the functional role of the histidyl-FAD bond was studied. Three His(422) mutants (H422A, H422T, and H422C) were purified, which all contained tightly but noncovalen ...

    By mutating the target residue of covalent flavinylation in vanillyl-alcohol oxidase, the functional role of the histidyl-FAD bond was studied. Three His(422) mutants (H422A, H422T, and H422C) were purified, which all contained tightly but noncovalently bound FAD. Steady state kinetics revealed that the mutants have retained enzyme activity, although the turnover rates have decreased by 1 order of magnitude. Stopped-flow analysis showed that the H422A mutant is still able to form a stable binary complex of reduced enzyme and a quinone methide product intermediate, a crucial step during vanillyl-alcohol oxidase-mediated catalysis. The only significant change in the catalytic cycle of the H422A mutant is a marked decrease in reduction rate. Redox potentials of both wild type and H422A vanillyl-alcohol oxidase have been determined. During reduction of H422A, a large portion of the neutral flavin semiquinone is observed. Using suitable reference dyes, the redox potentials for the two one-electron couples have been determined: -17 and -113 mV. Reduction of wild type enzyme did not result in any formation of flavin semiquinone and revealed a remarkably high redox potential of +55 mV. The marked decrease in redox potential caused by the missing covalent histidyl-FAD bond is reflected in the reduced rate of substrate-mediated flavin reduction limiting the turnover rate. Elucidation of the crystal structure of the H422A mutant established that deletion of the histidyl-FAD bond did not result in any significant structural changes. These results clearly indicate that covalent interaction of the isoalloxazine ring with the protein moiety can markedly increase the redox potential of the flavin cofactor, thereby facilitating redox catalysis. Thus, formation of a histidyl-FAD bond in specific flavoenzymes might have evolved as a way to contribute to the enhancement of their oxidative power.


    Related Citations: 
    • Crystallization and Preliminary X-Ray Analysis of the Flavoenzyme Vanillyl-Alcohol Oxidase from Penicillium Simplicissimum
      Mattevi, A.,Fraaije, M.W.,Coda, A.,Van Berkel, W.J.
      (1997) Proteins: Struct.,Funct., Genet. 27: 601


    Organizational Affiliation

    Department of Genetics, University of Pavia, via Abbiategrasso 207, 27100 Pavia, Italy. M.W.Fraaije@chem.rug.nl




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
VANILLYL-ALCOHOL OXIDASE
A, B
560Penicillium simplicissimumMutation(s): 1 
Gene Names: VAOA
EC: 1.1.3.38
Find proteins for P56216 (Penicillium simplicissimum)
Go to UniProtKB:  P56216
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A, B
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
FAD
Query on FAD

Download SDF File 
Download CCD File 
A, B
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
FADKd: 4600000 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.210 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 129.660α = 90.00
b = 129.660β = 90.00
c = 132.300γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
CCP4phasing
DENZOdata reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-09-20
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance