3HG2

Human alpha-galactosidase catalytic mechanism 1. Empty active site


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 

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Ligand Structure Quality Assessment 


This is version 2.1 of the entry. See complete history


Literature

Catalytic mechanism of human alpha-galactosidase.

Guce, A.I.Clark, N.E.Salgado, E.N.Ivanen, D.R.Kulminskaya, A.A.Brumer, H.Garman, S.C.

(2010) J Biol Chem 285: 3625-3632

  • DOI: https://doi.org/10.1074/jbc.M109.060145
  • Primary Citation of Related Structures:  
    3HG2, 3HG3, 3HG4, 3HG5

  • PubMed Abstract: 

    The enzyme alpha-galactosidase (alpha-GAL, also known as alpha-GAL A; E.C. 3.2.1.22) is responsible for the breakdown of alpha-galactosides in the lysosome. Defects in human alpha-GAL lead to the development of Fabry disease, a lysosomal storage disorder characterized by the buildup of alpha-galactosylated substrates in the tissues. alpha-GAL is an active target of clinical research: there are currently two treatment options for Fabry disease, recombinant enzyme replacement therapy (approved in the United States in 2003) and pharmacological chaperone therapy (currently in clinical trials). Previously, we have reported the structure of human alpha-GAL, which revealed the overall structure of the enzyme and established the locations of hundreds of mutations that lead to the development of Fabry disease. Here, we describe the catalytic mechanism of the enzyme derived from x-ray crystal structures of each of the four stages of the double displacement reaction mechanism. Use of a difluoro-alpha-galactopyranoside allowed trapping of a covalent intermediate. The ensemble of structures reveals distortion of the ligand into a (1)S(3) skew (or twist) boat conformation in the middle of the reaction cycle. The high resolution structures of each step in the catalytic cycle will allow for improved drug design efforts on alpha-GAL and other glycoside hydrolase family 27 enzymes by developing ligands that specifically target different states of the catalytic cycle. Additionally, the structures revealed a second ligand-binding site suitable for targeting by novel pharmacological chaperones.


  • Organizational Affiliation

    Departments of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Alpha-galactosidase A
A, B
398Homo sapiensMutation(s): 0 
Gene Names: GLA
EC: 3.2.1.22
UniProt & NIH Common Fund Data Resources
Find proteins for P06280 (Homo sapiens)
Explore P06280 
Go to UniProtKB:  P06280
PHAROS:  P06280
GTEx:  ENSG00000102393 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP06280
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-L-fucopyranose-(1-6)-2-acetamido-2-deoxy-beta-D-glucopyranose
C
2N-Glycosylation
Glycosylation Resources
GlyTouCan:  G86851RC
GlyCosmos:  G86851RC
GlyGen:  G86851RC
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
D, E
3N-Glycosylation
Glycosylation Resources
GlyTouCan:  G15407YE
GlyCosmos:  G15407YE
GlyGen:  G15407YE
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download Ideal Coordinates CCD File 
F [auth A],
J [auth B],
K [auth B]
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
GAL
Query on GAL

Download Ideal Coordinates CCD File 
L [auth B]beta-D-galactopyranose
C6 H12 O6
WQZGKKKJIJFFOK-FPRJBGLDSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
M [auth B]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
ACY
Query on ACY

Download Ideal Coordinates CCD File 
I [auth A],
N [auth B],
O [auth B]
ACETIC ACID
C2 H4 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 90.813α = 90
b = 90.813β = 90
c = 217.166γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-11-24
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2023-09-06
    Changes: Data collection, Database references, Refinement description, Structure summary