7BYV

Crystal structure of exo-beta-1,3-galactanase from Phanerochaete chrysosporium Pc1,3Gal43A E208Q with beta-1,3-galactotriose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.170 

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Literature

Unique active-site and subsite features in the arabinogalactan-degrading GH43 exo-beta-1,3-galactanase from Phanerochaete chrysosporium .

Matsuyama, K.Kishine, N.Fujimoto, Z.Sunagawa, N.Kotake, T.Tsumuraya, Y.Samejima, M.Igarashi, K.Kaneko, S.

(2020) J Biol Chem 295: 18539-18552

  • DOI: https://doi.org/10.1074/jbc.RA120.016149
  • Primary Citation of Related Structures:  
    7BYS, 7BYT, 7BYV, 7BYX

  • PubMed Abstract: 

    Arabinogalactan proteins (AGPs) are plant proteoglycans with functions in growth and development. However, these functions are largely unexplored, mainly because of the complexity of the sugar moieties. These carbohydrate sequences are generally analyzed with the aid of glycoside hydrolases. The exo-β-1,3-galactanase is a glycoside hydrolase from the basidiomycete Phanerochaete chrysosporium ( Pc 1,3Gal43A), which specifically cleaves AGPs. However, its structure is not known in relation to its mechanism bypassing side chains. In this study, we solved the apo and liganded structures of Pc 1,3Gal43A, which reveal a glycoside hydrolase family 43 subfamily 24 (GH43_sub24) catalytic domain together with a carbohydrate-binding module family 35 (CBM35) binding domain. GH43_sub24 is known to lack the catalytic base Asp conserved among other GH43 subfamilies. Our structure in combination with kinetic analyses reveals that the tautomerized imidic acid group of Gln 263 serves as the catalytic base residue instead. Pc 1,3Gal43A has three subsites that continue from the bottom of the catalytic pocket to the solvent. Subsite -1 contains a space that can accommodate the C-6 methylol of Gal, enabling the enzyme to bypass the β-1,6-linked galactan side chains of AGPs. Furthermore, the galactan-binding domain in CBM35 has a different ligand interaction mechanism from other sugar-binding CBM35s, including those that bind galactomannan. Specifically, we noted a Gly → Trp substitution, which affects pyranose stacking, and an Asp → Asn substitution in the binding pocket, which recognizes β-linked rather than α-linked Gal residues. These findings should facilitate further structural analysis of AGPs and may also be helpful in engineering designer enzymes for efficient biomass utilization.


  • Organizational Affiliation

    Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Galactan 1,3-beta-galactosidase428Phanerodontia chrysosporiumMutation(s): 1 
Gene Names: Pc13Gal43A
EC: 3.2.1.145
UniProt
Find proteins for Q50KB2 (Phanerodontia chrysosporium)
Explore Q50KB2 
Go to UniProtKB:  Q50KB2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ50KB2
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
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
B
3N-Glycosylation
Glycosylation Resources
GlyTouCan:  G15407YE
GlyCosmos:  G15407YE
GlyGen:  G15407YE
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-galactopyranose-(1-3)-beta-D-galactopyranose-(1-3)-beta-D-galactopyranose
C
3N/A
Glycosylation Resources
GlyTouCan:  G59103JC
GlyCosmos:  G59103JC
GlyGen:  G59103JC
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.170 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.08α = 90
b = 50.412β = 111.328
c = 75.698γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
REFMACrefinement
Cootmodel building
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Japan Society for the Promotion of Science (JSPS)Japan18H05494

Revision History  (Full details and data files)

  • Version 1.0: 2020-11-04
    Type: Initial release
  • Version 1.1: 2021-01-13
    Changes: Database references
  • Version 1.2: 2023-11-29
    Changes: Data collection, Database references, Refinement description