3GXP

Crystal structure of acid-alpha-galactosidase A complexed with galactose at pH 4.5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.204 

wwPDB Validation 3D Report Full Report



Literature

Effects of pH and iminosugar pharmacological chaperones on lysosomal glycosidase structure and stability.

Lieberman, R.L.D'aquino, J.A.Ringe, D.Petsko, G.A.

(2009) Biochemistry 48: 4816-4827

  • DOI: 10.1021/bi9002265
  • Primary Citation of Related Structures:  
    3GXM, 3GXN, 3GXP, 3GXD, 3GXF, 3GXI, 3GXT

  • PubMed Abstract: 
  • Human lysosomal enzymes acid-beta-glucosidase (GCase) and acid-alpha-galactosidase (alpha-Gal A) hydrolyze the sphingolipids glucosyl- and globotriaosylceramide, respectively, and mutations in these enzymes lead to the lipid metabolism disorders Gauc ...

    Human lysosomal enzymes acid-beta-glucosidase (GCase) and acid-alpha-galactosidase (alpha-Gal A) hydrolyze the sphingolipids glucosyl- and globotriaosylceramide, respectively, and mutations in these enzymes lead to the lipid metabolism disorders Gaucher and Fabry disease, respectively. We have investigated the structure and stability of GCase and alpha-Gal A in a neutral-pH environment reflective of the endoplasmic reticulum and an acidic-pH environment reflective of the lysosome. These details are important for the development of pharmacological chaperone therapy for Gaucher and Fabry disease, in which small molecules bind mutant enzymes in the ER to enable the mutant enzyme to meet quality control requirements for lysosomal trafficking. We report crystal structures of apo GCase at pH 4.5, at pH 5.5, and in complex with the pharmacological chaperone isofagomine (IFG) at pH 7.5. We also present thermostability analysis of GCase at pH 7.4 and 5.2 using differential scanning calorimetry. We compare our results with analogous experiments using alpha-Gal A and the chaperone 1-deoxygalactonijirimycin (DGJ), including the first structure of alpha-Gal A with DGJ. Both GCase and alpha-Gal A are more stable at lysosomal pH with and without their respective iminosugars bound, and notably, the stability of the GCase-IFG complex is pH sensitive. We show that the conformations of the active site loops in GCase are sensitive to ligand binding but not pH, whereas analogous galactose- or DGJ-dependent conformational changes in alpha-Gal A are not seen. Thermodynamic parameters obtained from alpha-Gal A unfolding indicate two-state, van't Hoff unfolding in the absence of the iminosugar at neutral and lysosomal pH, and non-two-state unfolding in the presence of DGJ. Taken together, these results provide insight into how GCase and alpha-Gal A are thermodynamically stabilized by iminosugars and suggest strategies for the development of new pharmacological chaperones for lysosomal storage disorders.


    Organizational Affiliation

    Structural Neurology Lab at the Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA. raquel.lieberman@chemistry.gatech.edu



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Alpha-galactosidase AAB398Homo sapiensMutation(s): 0 
Gene Names: GLA
EC: 3.2.1.22 (PDB Primary Data), 3.2.1.47 (UniProt)
Find proteins for P06280 (Homo sapiens)
Explore P06280 
Go to UniProtKB:  P06280
NIH Common Fund Data Resources
PHAROS  P06280
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
C
3 N-Glycosylation Oligosaccharides Interaction
Entity ID: 3
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
D, E, F, G
2 N-Glycosylation Oligosaccharides Interaction
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

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A
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
GLA
Query on GLA

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A, B
alpha-D-galactopyranose
C6 H12 O6
WQZGKKKJIJFFOK-PHYPRBDBSA-N
 Ligand Interaction
MAN
Query on MAN

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B
alpha-D-mannopyranose
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
TAM
Query on TAM

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A
TRIS(HYDROXYETHYL)AMINOMETHANE
C7 H17 N O3
GKODZWOPPOTFGA-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

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A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.204 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 89.51α = 90
b = 89.51β = 90
c = 215.927γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

  • Deposited Date: 2009-04-02 
  • Released Date: 2009-05-05 
  • Deposition Author(s): Lieberman, R.L.

Revision History 

  • Version 1.0: 2009-05-05
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Refinement description, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary