glycoside hydrolase family 77 4-alpha-glucanotransferase from thermus brockianus

Experimental Data Snapshot

  • Resolution: 2.36 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.215 

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Structural and Functional Analysis of Substrate Recognition by the 250S Loop in Amylomaltase from Thermus Brockianus.

Jung, J.-H.Jung, T.-Y.Seo, D.Yoon, S.-M.Choi, H.Park, B.C.Park, C.-S.Woo, E.-J.

(2011) Proteins 79: 633

  • DOI: https://doi.org/10.1002/prot.22911
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Amylomaltase, or 4-α-glucanotransferase (EC, is involved in glycogen and maltooligosaccharide metabolism in microorganisms, catalyzing both the hydrolysis and transfer of an α-1,4-oligosacchraride to other sugar molecules. In this study, we determined the crystal structure of amylomaltase from Thermus brockianus at a resolution of 2.3 Å and conducted a biochemical study to understand the detailed mechanism for its activity. Careful comparison with previous amylomaltase structures showed a pattern of conformational flexibility in the 250s loop with higher B-factor. Amylomaltase from T. brockianus exhibited a high transglycosylation factor for glucose and a lower value for maltose. Mutation of Gln256 resulted in increased K(m) for maltotriose and a sharp decrease of the transglycosylation factor for maltose, suggesting the involvement of Gln 256 in substrate binding between subsites +1 and +2. Mutation of Phe251 resulted in significantly lower glucose production but increased maltose production from maltopentose substrates, showing an altered substrate-binding affinity. The mutational data suggest the conformational flexibility of the loop may be involved in substrate binding in the GH77 family. Here, we present an action model of the 250s loop providing the molecular basis for the involvement of residues Phe251, Gln256, and Trp258 in the hydrolysis and transglycosylation activities in amylomaltase.

  • Organizational Affiliation

    Graduate School of Biotechnology and Institute of Life Science and Resources, Kyung Hee University, Yongin 446-701, Korea.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
4-ALPHA-GLUCANOTRANSFERASE500Thermus brockianusMutation(s): 0 
Find proteins for Q2VJA0 (Thermus brockianus)
Explore Q2VJA0 
Go to UniProtKB:  Q2VJA0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ2VJA0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.36 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.215 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 104.357α = 90
b = 104.357β = 90
c = 263.759γ = 120
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-10-27
    Type: Initial release
  • Version 1.1: 2011-08-31
    Changes: Database references, Derived calculations, Refinement description, Version format compliance
  • Version 1.2: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description