1E71

MYROSINASE FROM SINAPIS ALBA with bound ascorbate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.152 
  • R-Value Work: 0.127 

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This is version 2.0 of the entry. See complete history


Literature

High Resolution X-Ray Crystallography Shows that Ascorbate is a Cofactor for Myrosinase and Substitutes for the Function of the Catalytic Base

Burmeister, W.P.Cottaz, S.Rollin, P.Vasella, A.Henrissat, B.

(2000) J Biol Chem 275: 39385

  • DOI: 10.1074/jbc.M006796200
  • Primary Citation of Related Structures:  
    1E4M, 1E6Q, 1E6S, 1E6X, 1E70, 1E71, 1E72, 1E73

  • PubMed Abstract: 
  • Myrosinase, an S-glycosidase, hydrolyzes plant anionic 1-thio-beta-d-glucosides (glucosinolates) considered part of the plant defense system. Although O-glycosidases are ubiquitous, myrosinase is the only known S-glycosidase. Its active site is very similar to that of retaining O-glycosidases, but one of the catalytic residues in O-glycosidases, a carboxylate residue functioning as the general base, is replaced by a glutamine residue ...

    Myrosinase, an S-glycosidase, hydrolyzes plant anionic 1-thio-beta-d-glucosides (glucosinolates) considered part of the plant defense system. Although O-glycosidases are ubiquitous, myrosinase is the only known S-glycosidase. Its active site is very similar to that of retaining O-glycosidases, but one of the catalytic residues in O-glycosidases, a carboxylate residue functioning as the general base, is replaced by a glutamine residue. Myrosinase is strongly activated by ascorbic acid. Several binary and ternary complexes of myrosinase with different transition state analogues and ascorbic acid have been analyzed at high resolution by x-ray crystallography along with a 2-deoxy-2-fluoro-glucosyl enzyme intermediate. One of the inhibitors, d-gluconhydroximo-1,5-lactam, binds simultaneously with a sulfate ion to form a mimic of the enzyme-substrate complex. Ascorbate binds to a site distinct from the glucose binding site but overlapping with the aglycon binding site, suggesting that activation occurs at the second step of catalysis, i.e. hydrolysis of the glycosyl enzyme. A water molecule is placed perfectly for activation by ascorbate and for nucleophilic attack on the covalently trapped 2-fluoro-glucosyl-moiety. Activation of the hydrolysis of the glucosyl enzyme intermediate is further evidenced by the observation that ascorbate enhances the rate of reactivation of the 2-fluoro-glycosyl enzyme, leading to the conclusion that ascorbic acid substitutes for the catalytic base in myrosinase.


    Related Citations: 
    • The Crystal Structures of Sinapis Alba Myrosinase and a Covalent Glycosyl-Enzyme Intermediate Provide Insights Into the Substrate Recognition and Active-Site Machinery of an S-Glycosidase
      Burmeister, W.P., Cottaz, S., Driguez, H., Iori, R., Palmieri, S., Henrissat, B.
      (1997) Structure 5: 663

    Organizational Affiliation

    European Synchrotron Radiation Facility and Forschungszentrum Jülich, BP 220, F-38043 Grenoble cedex, France. wpb@embl-grenoble.fr



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
MYROSINASE MA1A [auth M]501Sinapis albaMutation(s): 0 
EC: 3.2.1.147
UniProt
Find proteins for P29736 (Sinapis alba)
Explore P29736 
Go to UniProtKB:  P29736
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranoseB [auth A]2N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G42666HT
GlyCosmos:  G42666HT
GlyGen:  G42666HT
Entity ID: 3
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
beta-D-xylopyranose-(1-2)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-3)]2-acetamido-2-deoxy-beta-D-glucopyranoseC [auth B]5N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G06206UV
GlyCosmos:  G06206UV
GlyGen:  G06206UV
Entity ID: 4
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
beta-D-xylopyranose-(1-2)-[alpha-D-mannopyranose-(1-3)][alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-3)]2-acetamido-2-deoxy-beta-D-glucopyranoseD [auth C]7N-Glycosylation Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G26295XE
GlyCosmos:  G26295XE
GlyGen:  G26295XE
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG (Subject of Investigation/LOI)
Query on NAG

Download Ideal Coordinates CCD File 
E [auth M], F [auth M], G [auth M], H [auth M], I [auth M], J [auth M]2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
ASC (Subject of Investigation/LOI)
Query on ASC

Download Ideal Coordinates CCD File 
K [auth M]ASCORBIC ACID
C6 H8 O6
CIWBSHSKHKDKBQ-JLAZNSOCSA-N
 Ligand Interaction
SO4
Query on SO4

Download Ideal Coordinates CCD File 
N [auth M], O [auth M], P [auth M], Q [auth M], R [auth M], S [auth M], T [auth M], U [auth M]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

Download Ideal Coordinates CCD File 
L [auth M], V [auth M], W [auth M], X [auth M], Y [auth M]GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
ZN
Query on ZN

Download Ideal Coordinates CCD File 
MZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.152 
  • R-Value Work: 0.127 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 135.3α = 90
b = 137.2β = 90
c = 80.6γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
Agrovatadata scaling
ROTAVATAdata scaling
X-PLORphasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

  • Deposited Date: 2000-08-23 
  • Released Date: 2001-01-05 
  • Deposition Author(s): Burmeister, W.P.

Revision History  (Full details and data files)

  • Version 1.0: 2001-01-05
    Type: Initial release
  • Version 1.1: 2011-11-30
    Changes: Derived calculations, Non-polymer description, Other, Structure summary, Version format compliance
  • Version 1.2: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Other, Structure summary