Crystal Structure of Anoxybacillus Alpha-amylase Provides Insights into a New Glycosyl Hydrolase Subclass

Experimental Data Snapshot

  • Resolution: 1.85 Å
  • R-Value Free: 0.193 
  • R-Value Work: 0.155 
  • R-Value Observed: 0.157 

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Crystal Structure of Anoxybacillus Alpha-Amylase Provides Insights Into Maltose Binding of a New Glycosyl Hydrolase Subclass.

Chai, K.P.Othman, N.F.B.Teh, A.Ho, K.L.Chan, K.Shamsir, M.S.Goh, K.M.Ng, C.L.

(2016) Sci Rep 6: 23126

  • DOI: https://doi.org/10.1038/srep23126
  • Primary Citation of Related Structures:  
    5A2A, 5A2B, 5A2C

  • PubMed Abstract: 

    A new subfamily of glycosyl hydrolase family GH13 was recently proposed for α-amylases from Anoxybacillus species (ASKA and ADTA), Geobacillus thermoleovorans (GTA, Pizzo, and GtamyII), Bacillus aquimaris (BaqA), and 95 other putative protein homologues. To understand this new GH13 subfamily, we report crystal structures of truncated ASKA (TASKA). ASKA is a thermostable enzyme capable of producing high levels of maltose. Unlike GTA, biochemical analysis showed that Ca(2+) ion supplementation enhances the catalytic activities of ASKA and TASKA. The crystal structures reveal the presence of four Ca(2+) ion binding sites, with three of these binding sites are highly conserved among Anoxybacillus α-amylases. This work provides structural insights into this new GH13 subfamily both in the apo form and in complex with maltose. Furthermore, structural comparison of TASKA and GTA provides an overview of the conformational changes accompanying maltose binding at each subsite.

  • Organizational Affiliation

    Universiti Teknologi Malaysia, Faculty of Biosciences and Medical Engineering, 81310 Skudai, Johor, Malaysia.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ANOXYBACILLUS ALPHA-AMYLASE497Anoxybacillus ayderensisMutation(s): 0 
Find proteins for I1VWH9 (Anoxybacillus ayderensis)
Explore I1VWH9 
Go to UniProtKB:  I1VWH9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupI1VWH9
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G07411ON
GlyCosmos:  G07411ON
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Resolution: 1.85 Å
  • R-Value Free: 0.193 
  • R-Value Work: 0.155 
  • R-Value Observed: 0.157 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.013α = 90
b = 65.296β = 90
c = 126.708γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-03-30
    Type: Initial release
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Non-polymer description, Other, Structure summary
  • Version 2.1: 2024-01-10
    Changes: Data collection, Database references, Refinement description, Structure summary