2JBV

Crystal structure of choline oxidase reveals insights into the catalytic mechanism


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.86 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.171 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

Role of Glu312 in Binding and Positioning of the Substrate for the Hydride Transfer Reaction in Choline Oxidase.

Quaye, O.Lountos, G.T.Fan, F.Orville, A.M.Gadda, G.

(2008) Biochemistry 47: 243

  • DOI: https://doi.org/10.1021/bi7017943
  • Primary Citation of Related Structures:  
    2JBV

  • PubMed Abstract: 

    Choline oxidase catalyzes the oxidation of choline to glycine betaine, a compatible solute that accumulates in pathogenic bacteria and plants so they can withstand osmotic and temperature stresses. The crystal structure of choline oxidase was determined and refined to a resolution of 1.86 A with data collected at 100 K using synchrotron X-ray radiation. The structure reveals a covalent linkage between His99 Nepsilon2 and FAD C8M atoms, and a 123 A3 solvent-excluded cavity adjacent to the re face of the flavin. A hypothetical model for choline docked into the cavity suggests that several aromatic residues and Glu312 may orient the cationic substrate for efficient catalysis. The role of the negative charge on Glu312 was investigated by engineering variant enzymes in which Glu312 was replaced with alanine, glutamine, or aspartate. The Glu312Ala enzyme was inactive. The Glu312Gln enzyme exhibited a Kd value for choline at least 500 times larger than that of the wild-type enzyme. The Glu312Asp enzyme had a kcat/KO2 value similar to that of the wild-type enzyme but kcat and kcat/Km values that were 230 and 35 times lower, respectively, than in the wild-type enzyme. These data are consistent with the spatial location of the negative charge on residue 312 being important for the oxidation of the alcohol substrate. Solvent viscosity and substrate kinetic isotope effects suggest the presence of an internal equilibrium in the Glu312Asp enzyme prior to the hydride transfer reaction. Altogether, the crystallographic and mechanistic data suggest that Glu312 is important for binding and positioning of the substrate in the active site of choline oxidase.


  • Organizational Affiliation

    Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-4098, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CHOLINE OXIDASE
A, B
546Arthrobacter globiformisMutation(s): 0 
EC: 1.1.3.17
UniProt
Find proteins for Q7X2H8 (Arthrobacter globiformis)
Explore Q7X2H8 
Go to UniProtKB:  Q7X2H8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7X2H8
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
FAO
Query on FAO

Download Ideal Coordinates CCD File 
C [auth A],
G [auth B]
[(2R,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl]methyl (2R,3S,4S)-5-[(4aS,10aR)-7,8-dimethyl-2,4-dioxo-1,3,4,4a,5,10a-hexahydrobenzo[g]pteridin-10(2H)-yl]-2,3,4-trihydroxypentyl dihydrogen diphosphate
C27 H37 N9 O15 P2
VSWYNLHGQAGAHX-AWYOOINRSA-N
DMS
Query on DMS

Download Ideal Coordinates CCD File 
D [auth A],
H [auth B]
DIMETHYL SULFOXIDE
C2 H6 O S
IAZDPXIOMUYVGZ-UHFFFAOYSA-N
UNX
Query on UNX

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A],
I [auth B],
J [auth B]
UNKNOWN ATOM OR ION
X
Binding Affinity Annotations 
IDSourceBinding Affinity
FAO PDBBind:  2JBV Kd: 2.90e+5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.86 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.171 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.355α = 90
b = 84.355β = 90
c = 343.45γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
SCALEPACKdata scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-12-25
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description