3OJN

Structure of Mn-substituted Homoprotocatechuate 2,3-Dioxygenase at 1.65 Ang resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.177 
  • R-Value Work: 0.148 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

A hyperactive cobalt-substituted extradiol-cleaving catechol dioxygenase.

Fielding, A.J.Kovaleva, E.G.Farquhar, E.R.Lipscomb, J.D.Que, L.

(2011) J.Biol.Inorg.Chem. 16: 341-355

  • DOI: 10.1007/s00775-010-0732-0
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD) has an Fe(II) center in its active site that can be replaced with Mn(II) or Co(II). Whereas Mn-HPCD exhibits steady-state kinetic parameters comparable to those of Fe-HPCD, Co-HPCD ...

    Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD) has an Fe(II) center in its active site that can be replaced with Mn(II) or Co(II). Whereas Mn-HPCD exhibits steady-state kinetic parameters comparable to those of Fe-HPCD, Co-HPCD behaves somewhat differently, exhibiting significantly higher [Formula: see text] and k (cat). The high activity of Co-HPCD is surprising, given that cobalt has the highest standard M(III/II) redox potential of the three metals. Comparison of the X-ray crystal structures of the resting and substrate-bound forms of Fe-HPCD, Mn-HPCD, and Co-HPCD shows that metal substitution has no effect on the local ligand environment, the conformational integrity of the active site, or the overall protein structure, suggesting that the protein structure does not differentially tune the potential of the metal center. Analysis of the steady-state kinetics of Co-HPCD suggests that the Co(II) center alters the relative rate constants for the interconversion of intermediates in the catalytic cycle but still allows the dioxygenase reaction to proceed efficiently. When compared with the kinetic data for Fe-HPCD and Mn-HPCD, these results show that dioxygenase catalysis can proceed at high rates over a wide range of metal redox potentials. This is consistent with the proposed mechanism in which the metal mediates electron transfer between the catechol substrate and O(2) to form the postulated [M(II)(semiquinone)superoxo] reactive species. These kinetic differences and the spectroscopic properties of Co-HPCD provide new tools with which to explore the unique O(2) activation mechanism associated with the extradiol dioxygenase family.


    Organizational Affiliation

    Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street, Minneapolis, MN 55455, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Homoprotocatechuate 2,3-dioxygenase
A, B, C, D
365Brevibacterium fuscumMutation(s): 0 
Find proteins for Q45135 (Brevibacterium fuscum)
Go to UniProtKB:  Q45135
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

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A, B, C, D
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
CL
Query on CL

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

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Download CCD File 
B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
PG4
Query on PG4

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Download CCD File 
B, C, D
TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
 Ligand Interaction
P6G
Query on P6G

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Download CCD File 
A, B, C, D
HEXAETHYLENE GLYCOL
POLYETHYLENE GLYCOL PEG400
C12 H26 O7
IIRDTKBZINWQAW-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.177 
  • R-Value Work: 0.148 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 110.542α = 90.00
b = 151.497β = 90.00
c = 96.359γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
MOLREPphasing
SCALAdata scaling
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-12-29
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance