3WY4

Crystal structure of alpha-glucosidase mutant E271Q in complex with maltose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history


Literature

Structural analysis of the alpha-glucosidase HaG provides new insights into substrate specificity and catalytic mechanism

Shen, X.Saburi, W.Gai, Z.Kato, K.Ojima-Kato, T.Yu, J.Komoda, K.Kido, Y.Matsui, H.Mori, H.Yao, M.

(2015) Acta Crystallogr D Biol Crystallogr 71: 1382-1391

  • DOI: https://doi.org/10.1107/S139900471500721X
  • Primary Citation of Related Structures:  
    3WY1, 3WY2, 3WY3, 3WY4

  • PubMed Abstract: 

    α-Glucosidases, which catalyze the hydrolysis of the α-glucosidic linkage at the nonreducing end of the substrate, are important for the metabolism of α-glucosides. Halomonas sp. H11 α-glucosidase (HaG), belonging to glycoside hydrolase family 13 (GH13), only has high hydrolytic activity towards the α-(1 → 4)-linked disaccharide maltose among naturally occurring substrates. Although several three-dimensional structures of GH13 members have been solved, the disaccharide specificity and α-(1 → 4) recognition mechanism of α-glucosidase are unclear owing to a lack of corresponding substrate-bound structures. In this study, four crystal structures of HaG were solved: the apo form, the glucosyl-enzyme intermediate complex, the E271Q mutant in complex with its natural substrate maltose and a complex of the D202N mutant with D-glucose and glycerol. These structures explicitly provide insights into the substrate specificity and catalytic mechanism of HaG. A peculiar long β → α loop 4 which exists in α-glucosidase is responsible for the strict recognition of disaccharides owing to steric hindrance. Two residues, Thr203 and Phe297, assisted with Gly228, were found to determine the glycosidic linkage specificity of the substrate at subsite +1. Furthermore, an explanation of the α-glucosidase reaction mechanism is proposed based on the glucosyl-enzyme intermediate structure.


  • Organizational Affiliation

    Faculty of Advanced Life Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Alpha-glucosidase
A, B
538Halomonas sp. H11Mutation(s): 1 
Gene Names: aglA
EC: 3.2.1.20
UniProt
Find proteins for H3K096 (Halomonas sp. H11)
Explore H3K096 
Go to UniProtKB:  H3K096
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupH3K096
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
C
2N/A
Glycosylation Resources
GlyTouCan:  G07411ON
GlyCosmos:  G07411ON
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 111.464α = 90
b = 181.062β = 90
c = 51.933γ = 90
Software Package:
Software NamePurpose
SERGUIdata collection
PHASERphasing
PHENIXrefinement
XDSdata reduction
XDSdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-06-10
    Type: Initial release
  • Version 1.1: 2017-11-22
    Changes: Refinement description
  • Version 1.2: 2018-03-21
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Database references, Derived calculations, Non-polymer description, Structure summary