1SZE

L230A mutant flavocytochrome b2 with benzoylformate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.200 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Altered Substrate Specificity in Flavocytochrome b(2): Structural Insights into the Mechanism of l-Lactate Dehydrogenation

Mowat, C.G.Wehenkel, A.Green, A.J.Walkinshaw, M.D.Reid, G.A.Chapman, S.K.

(2004) Biochemistry 43: 9519-9526

  • DOI: 10.1021/bi049263m
  • Primary Citation of Related Structures:  1SZF, 1SZG

  • PubMed Abstract: 
  • Flavocytochrome b(2) from Saccharomyces cerevisiae is a l-lactate/cytochrome c oxidoreductase belonging to a large family of 2-hydroxyacid-dependent flavoenzymes. The crystal structure of the enzyme, with pyruvate bound at the active site, has been d ...

    Flavocytochrome b(2) from Saccharomyces cerevisiae is a l-lactate/cytochrome c oxidoreductase belonging to a large family of 2-hydroxyacid-dependent flavoenzymes. The crystal structure of the enzyme, with pyruvate bound at the active site, has been determined [Xia, Z.-X., and Mathews, F. S. (1990) J. Mol. Biol. 212, 837-863]. The authors indicate that the methyl group of pyruvate is in close contact with Ala198 and Leu230. These two residues are not well-conserved throughout the family of (S)-2-hydroxy acid oxidases/dehydrogenases. Thus, to probe substrate specificity in flavocytochrome b(2), these residues have been substituted by glycine and alanine, respectively. Kinetic studies on the L230A mutant enzyme and the A198G/L230A double mutant enzyme indicate a change in substrate selectivity for the enzyme toward larger (S)-2-hydroxy acids. In particular, the L230A enzyme is more efficient at utilizing (S)-2-hydroxyoctanoate by a factor of 40 as compared to the wild-type enzyme [Daff, S., Manson, F. D. C., Reid, G. A., and Chapman, S. K. (1994) Biochem. J. 301, 829-834], and the A198G/L230A double mutant enzyme is 6-fold more efficient with the aromatic substrate l-mandelate than it is with l-lactate [Sinclair, R., Reid, G. A., and Chapman, S. K. (1998) Biochem. J. 333, 117-120]. To complement these solution studies, we have solved the structure of the A198G/L230A enzyme in complex with pyruvate and as the FMN-sulfite adduct (both to 2.7 A resolution). We have also obtained the structure of the L230A mutant enzyme in complex with phenylglyoxylate (the product of mandelate oxidation) to 3.0 A resolution. These structures reveal the increased active-site volume available for binding larger substrates, while also confirming that the integrity of the interactions important for catalysis is maintained. In addition to this, the mode of binding of the bulky phenylglyoxylate at the active site is in accordance with the operation of a hydride transfer mechanism for substrate oxidation/flavin reduction in flavocytochrome b(2), whereas a mechanism involving the formation of a carbanion intermediate would appear to be sterically prohibited.


    Organizational Affiliation

    School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cytochrome b2, mitochondrial
A, B
511Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Gene Names: CYB2
EC: 1.1.2.3
Find proteins for P00175 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to UniProtKB:  P00175
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FMN
Query on FMN

Download SDF File 
Download CCD File 
A, B
FLAVIN MONONUCLEOTIDE
RIBOFLAVIN MONOPHOSPHATE
C17 H21 N4 O9 P
FVTCRASFADXXNN-SCRDCRAPSA-N
 Ligand Interaction
173
Query on 173

Download SDF File 
Download CCD File 
A, B
BENZOYL-FORMIC ACID
OXO(PHENYL)ACETIC ACID
C8 H6 O3
FAQJJMHZNSSFSM-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.200 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 163.027α = 90.00
b = 163.027β = 90.00
c = 112.473γ = 120.00
Software Package:
Software NamePurpose
AMoREphasing
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-07-27
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance