4Z6P

Structure of H200Q variant of Homoprotocatechuate 2,3-Dioxygenase from B.fuscum in complex with HPCA at 1.75 Ang resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.177 
  • R-Value Work: 0.146 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine 200.

Kovaleva, E.G.Rogers, M.S.Lipscomb, J.D.

(2015) Biochemistry 54: 5329-5339

  • DOI: 10.1021/acs.biochem.5b00709
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by ...

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady-state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures determined at 1.35-1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild-type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second-sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in the steric bulk and charge of the residue at position 200 appear to be capable of altering the rate-limiting step in catalysis and, perhaps, the nature of the reactive species.


    Organizational Affiliation

    Institute of Molecular and Cellular Biology, University of Leeds , Leeds LS2 9JT, U.K.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Homoprotocatechuate 2,3-dioxygenase
A, B, C, D
365Brevibacterium fuscumMutation(s): 1 
Find proteins for Q45135 (Brevibacterium fuscum)
Go to UniProtKB:  Q45135
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
DHY
Query on DHY

Download SDF File 
Download CCD File 
C
2-(3,4-DIHYDROXYPHENYL)ACETIC ACID
C8 H8 O4
CFFZDZCDUFSOFZ-UHFFFAOYSA-N
 Ligand Interaction
CL
Query on CL

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Download CCD File 
A, B, D
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
PG4
Query on PG4

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Download CCD File 
A
TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
 Ligand Interaction
P6G
Query on P6G

Download SDF File 
Download CCD File 
A, B, C, D
HEXAETHYLENE GLYCOL
POLYETHYLENE GLYCOL PEG400
C12 H26 O7
IIRDTKBZINWQAW-UHFFFAOYSA-N
 Ligand Interaction
FE2
Query on FE2

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Download CCD File 
A, B, C, D
FE (II) ION
Fe
CWYNVVGOOAEACU-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.177 
  • R-Value Work: 0.146 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 110.794α = 90.00
b = 151.235β = 90.00
c = 96.388γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
SCALAdata scaling
MOLREPphasing
REFMACrefinement
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research CouncilUnited KingdomBB/H001905/1
National Institutes of Health/National Institute of General Medical SciencesUnited StatesGM 24689

Revision History 

  • Version 1.0: 2015-08-26
    Type: Initial release
  • Version 1.1: 2015-09-16
    Type: Database references
  • Version 1.2: 2017-09-20
    Type: Author supporting evidence, Database references, Derived calculations, Structure summary