2I0K

Cholesterol Oxidase from Brevibacterium sterolicum- His121Ala Mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.167 
  • R-Value Work: 0.148 
  • R-Value Observed: 0.149 

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This is version 1.2 of the entry. See complete history


Literature

Structural and kinetic analyses of the H121A mutant of cholesterol oxidase.

Lim, L.Molla, G.Guinn, N.Ghisla, S.Pollegioni, L.Vrielink, A.

(2006) Biochem J 400: 13-22

  • DOI: 10.1042/BJ20060664
  • Primary Citation of Related Structures:  
    2I0K

  • PubMed Abstract: 
  • Cholesterol oxidase is a monomeric flavoenzyme that catalyses the oxidation of cholesterol to cholest-5-en-3-one followed by isomerization to cholest-4-en-3-one. The enzyme from Brevibacterium sterolicum contains the FAD cofactor covalently bound to His121 ...

    Cholesterol oxidase is a monomeric flavoenzyme that catalyses the oxidation of cholesterol to cholest-5-en-3-one followed by isomerization to cholest-4-en-3-one. The enzyme from Brevibacterium sterolicum contains the FAD cofactor covalently bound to His121. It was previously demonstrated that the H121A substitution results in a approximately 100 mV decrease in the midpoint redox potential and a approximately 40-fold decrease in turnover number compared to wild-type enzyme [Motteran, Pilone, Molla, Ghisla and Pollegioni (2001) Journal of Biological Chemistry 276, 18024-18030]. A detailed kinetic analysis of the H121A mutant enzyme shows that the decrease in turnover number is largely due to a corresponding decrease in the rate constant of flavin reduction, whilst the re-oxidation reaction is only marginally altered and the isomerization reaction is not affected by the substitution and precedes product dissociation. The X-ray structure of the mutant protein, determined to 1.7 A resolution (1 A identical with 0.1 nm), reveals only minor changes in the overall fold of the protein, namely: two loops have slight movements and a tryptophan residue changes conformation by a rotation of 180 degrees about chi1 compared to the native enzyme. Comparison of the isoalloxazine ring moiety of the FAD cofactor between the structures of the native and mutant proteins shows a change from a non-planar to a planar geometry (resulting in a more tetrahedral-like geometry for N5). This change is proposed to be a major factor contributing to the observed alteration in redox potential. Since a similar distortion of the flavin has not been observed in other covalent flavoproteins, it is proposed to represent a specific mode to facilitate flavin reduction in covalent cholesterol oxidase.


    Related Citations: 
    • Oxygen access to the active site of cholesterol oxidase through a narrow channel is gated by an Arg-Glu pair.
      Coulombe, R., Yue, K.Q., Ghisla, S., Vrielink, A.
      (2001) J Biol Chem 276: 30435

    Organizational Affiliation

    Department of Chemistry and Biochemistry, Sinsheimer Laboratory, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
OxidoreductaseA561Brevibacterium sterolicumMutation(s): 1 
EC: 1.1.3.6
UniProt
Find proteins for Q7SID9 (Brevibacterium sterolicum)
Explore Q7SID9 
Go to UniProtKB:  Q7SID9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7SID9
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FAD
Query on FAD

Download Ideal Coordinates CCD File 
F [auth A]FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
CAC
Query on CAC

Download Ideal Coordinates CCD File 
C [auth A],
D [auth A]
CACODYLATE ION
C2 H6 As O2
OGGXGZAMXPVRFZ-UHFFFAOYSA-M
 Ligand Interaction
GOL
Query on GOL

Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
I [auth A]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
MN
Query on MN

Download Ideal Coordinates CCD File 
B [auth A],
E [auth A]
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.167 
  • R-Value Work: 0.148 
  • R-Value Observed: 0.149 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 140.635α = 90
b = 85.851β = 112.48
c = 78.755γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
ADSCdata collection
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

  • Deposited Date: 2006-08-10 
  • Released Date: 2007-12-11 
  • Deposition Author(s): Vrielink, A., Lim, L.

Revision History  (Full details and data files)

  • Version 1.0: 2007-12-11
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references, Derived calculations