Bombyx mori GH32 beta-fructofuranosidase BmSUC1 mutant D63A in complex with sucrose

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.216 

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Structural insight into the substrate specificity of Bombyx mori beta-fructofuranosidase belonging to the glycoside hydrolase family 32.

Miyazaki, T.Oba, N.Park, E.Y.

(2020) Insect Biochem Mol Biol 127: 103494-103494

  • DOI: https://doi.org/10.1016/j.ibmb.2020.103494
  • Primary Citation of Related Structures:  
    7BWB, 7BWC

  • PubMed Abstract: 

    Sucrose-hydrolyzing enzymes are largely divided into β-fructofuranosidase and sucrose α-glucosidase. The domestic silkworm Bombyx mori possesses both enzymes, BmSUC1 and BmSUH, belonging to the glycoside hydrolase family 32 (GH32) and GH13, respectively. BmSUC1 was presumed to be acquired by horizontal gene transfer from bacteria based on phylogenetic analysis and related to tolerance to sugar-mimic alkaloids contained in mulberry latex. Here we investigated the substrate specificity of recombinant BmSUC1 that can hydrolyze not only sucrose but also fructooligosaccharides and fructans, and revealed that the enzyme was competitively inhibited by 1,4-dideoxy-1,4-imino-D-arabinitol, one of the alkaloids. Moreover, the crystal structures of BmSUC1 in apo form and complex with sucrose were determined, and the active site pocket was shallow and suitable for shorter substrates but was related to more relaxed substrate specificity than the strict sucrose α-glucosidase BmSUH. Considering together with the distribution of BmSUC1-orthologous genes in many lepidopterans, our results suggest that BmSUC1 contributes to the digestion of fructooligosaccharides and fructans derived from feed plants.

  • Organizational Affiliation

    Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan; Department of Applied Life Sciences, Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan. Electronic address: miyazaki.takatsugu@shizuoka.ac.jp.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Beta-fructofuranosidase488Bombyx moriMutation(s): 0 
Gene Names: BmSuc1Suc1
Find proteins for A0A6F8Z6Y2 (Bombyx mori)
Explore A0A6F8Z6Y2 
Go to UniProtKB:  A0A6F8Z6Y2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A6F8Z6Y2
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G05551OP
GlyCosmos:  G05551OP
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.216 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 96.522α = 90
b = 118.459β = 90
c = 101.285γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Japan Society for the Promotion of Science (JSPS)Japan19K15748

Revision History  (Full details and data files)

  • Version 1.0: 2020-11-04
    Type: Initial release
  • Version 1.1: 2020-11-18
    Changes: Database references
  • Version 1.2: 2023-11-29
    Changes: Data collection, Database references, Derived calculations, Refinement description