X-ray Structure of The Mutant of Glycoside Hydrolase

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.165 

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Crystal structure of beta-galactosidase from Bacillus circulans ATCC 31382 (BgaD) and the construction of the thermophilic mutants.

Ishikawa, K.Kataoka, M.Yanamoto, T.Nakabayashi, M.Watanabe, M.Ishihara, S.Yamaguchi, S.

(2015) FEBS J 282: 2540-2552

  • DOI: https://doi.org/10.1111/febs.13298
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    β-Galactosidase (EC from Bacillus circulans ATCC 31382, designated BgaD, exhibits high transglycosylation activity to produce galacto-oligosaccharides. BgaD has been speculated to have a multiple domain architecture including a F5/8-type C domain or a discoidin domain in the C-terminal peptide region from amino acid sequence analysis. Here, we solved the first crystal structure of the C-terminal deletion mutant BgaD-D, consisting of sugar binding, Glyco_hydro, catalytic and bacterial Ig-like domains, at 2.5 Å. In the asymmetric unit, two molecules of BgaD-D were identified and the value of VM was estimated to be 5.0 Å(3) · Da(-1). It has been speculated that BgaD-D consists of four domains. From the structural analysis, however, we clarified that BgaD-D consists of five domains. We identified a new domain structure comprised of β-sheets in BgaD. The catalytic domain exhibits a TIM barrel structure with a small pocket suited for accommodating the disaccharides. Detailed structural information for the amino acid residues related to activity and substrate specificity was clarified in the catalytic domain. Furthermore, using the structural information, we successfully constructed some thermostable mutants via protein engineering method. Coordinates for the BgaD-D structure have been deposited in the Protein Data Bank under accession code 4YPJ.

  • Organizational Affiliation

    Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Higashi-hiroshima, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Beta galactosidase
A, B
810Niallia circulansMutation(s): 0 
Gene Names: bga
Find proteins for E5RWQ2 (Niallia circulans)
Explore E5RWQ2 
Go to UniProtKB:  E5RWQ2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE5RWQ2
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.165 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 161.415α = 90
b = 161.415β = 90
c = 275.29γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
MOLREPmodel building

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-04-29
    Type: Initial release
  • Version 1.1: 2015-07-15
    Changes: Database references
  • Version 1.2: 2017-05-31
    Changes: Structure summary
  • Version 1.3: 2024-03-20
    Changes: Data collection, Database references, Refinement description