8IBK

Crystal structure of Bacillus sp. AHU2216 GH13_31 Alpha-glucosidase E256Q/N258G in complex with maltotriose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.69 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.183 

Starting Model: experimental
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This is version 1.1 of the entry. See complete history


Literature

Alteration of Substrate Specificity and Transglucosylation Activity of GH13_31 alpha-Glucosidase from Bacillus sp. AHU2216 through Site-Directed Mutagenesis of Asn258 on beta → alpha Loop 5.

Auiewiriyanukul, W.Saburi, W.Ota, T.Yu, J.Kato, K.Yao, M.Mori, H.

(2023) Molecules 28

  • DOI: https://doi.org/10.3390/molecules28073109
  • Primary Citation of Related Structures:  
    8IBK, 8IDS

  • PubMed Abstract: 

    α-Glucosidase catalyzes the hydrolysis of α-d-glucosides and transglucosylation. Bacillus sp. AHU2216 α-glucosidase (BspAG13_31A), belonging to the glycoside hydrolase family 13 subfamily 31, specifically cleaves α-(1→4)-glucosidic linkages and shows high disaccharide specificity. We showed previously that the maltose moiety of maltotriose (G3) and maltotetraose (G4), covering subsites +1 and +2 of BspAG13_31A, adopts a less stable conformation than the global minimum energy conformation. This unstable d-glucosyl conformation likely arises from steric hindrance by Asn258 on β→α loop 5 of the catalytic (β/α) 8 -barrel. In this study, Asn258 mutants of BspAG13_31A were enzymatically and structurally analyzed. N258G/P mutations significantly enhanced trisaccharide specificity. The N258P mutation also enhanced the activity toward sucrose and produced erlose from sucrose through transglucosylation. N258G showed a higher specificity to transglucosylation with p -nitrophenyl α-d-glucopyranoside and maltose than the wild type. E256Q/N258G and E258Q/N258P structures in complex with G3 revealed that the maltose moiety of G3 bound at subsites +1 and +2 adopted a relaxed conformation, whereas a less stable conformation was taken in E256Q. This structural difference suggests that stabilizing the G3 conformation enhances trisaccharide specificity. The E256Q/N258G-G3 complex formed an additional hydrogen bond between Met229 and the d-glucose residue of G3 in subsite +2, and this interaction may enhance transglucosylation.


  • Organizational Affiliation

    Research Faculty of Agriculture, Hokkaido Unifversity, Sapporo 060-8589, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Alpha-glucosidase563Bacillus sp. (in: firmicutes)Mutation(s): 2 
Gene Names: BspAG13A
UniProt
Find proteins for A0A2Z5WH92 (Bacillus sp)
Explore A0A2Z5WH92 
Go to UniProtKB:  A0A2Z5WH92
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A2Z5WH92
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranoseB [auth C]3N/A
Glycosylation Resources
GlyTouCan:  G96370VA
GlyCosmos:  G96370VA
GlyGen:  G96370VA
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.69 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.183 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.965α = 90
b = 88.991β = 90
c = 128.373γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2023-05-03
    Type: Initial release
  • Version 1.1: 2024-05-29
    Changes: Data collection