Structure of mature form of cathepsin B1 from Schistosoma mansoni

Experimental Data Snapshot

  • Resolution: 1.30 Å
  • R-Value Free: 0.177 
  • R-Value Work: 0.137 
  • R-Value Observed: 0.139 

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Activation route of the Schistosoma mansoni cathepsin B1 drug target: structural map with a glycosaminoglycan switch

Jilkova, A.Horn, M.Rezacova, P.Maresova, L.Fajtova, P.Brynda, J.Vondrasek, J.McKerrow, J.H.Caffrey, C.R.Mares, M.

(2014) Structure 22: 1786-1798

  • DOI: https://doi.org/10.1016/j.str.2014.09.015
  • Primary Citation of Related Structures:  
    4I04, 4I05, 4I07

  • PubMed Abstract: 

    Cathepsin B1 (SmCB1) is a digestive protease of the parasitic blood fluke Schistosoma mansoni and a drug target for the treatment of schistosomiasis, a disease that afflicts over 200 million people. SmCB1 is synthesized as an inactive zymogen in which the N-terminal propeptide blocks the active site. We investigated the activation of the zymogen by which the propeptide is proteolytically removed and its regulation by sulfated polysaccharides (SPs). We determined crystal structures of three molecular forms of SmCB1 along the activation pathway: the zymogen, an activation intermediate with a partially cleaved propeptide, and the mature enzyme. We demonstrate that SPs are essential for the autocatalytic activation of SmCB1, as they interact with a specific heparin-binding domain in the propeptide. An alternative activation route is mediated by an S. mansoni asparaginyl endopeptidase (legumain) which is downregulated by SPs, indicating that SPs act as a molecular switch between both activation mechanisms.

  • Organizational Affiliation

    Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague, Czech Republic; Department of Structural Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cathepsin B-like peptidase (C01 family)254Schistosoma mansoniMutation(s): 2 
Gene Names: cb1.1Smp_103610
Find proteins for Q8MNY2 (Schistosoma mansoni)
Explore Q8MNY2 
Go to UniProtKB:  Q8MNY2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8MNY2
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on CSD
Experimental Data & Validation

Experimental Data

  • Resolution: 1.30 Å
  • R-Value Free: 0.177 
  • R-Value Work: 0.137 
  • R-Value Observed: 0.139 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 33.143α = 90
b = 79.173β = 90
c = 90.483γ = 90
Software Package:
Software NamePurpose
HKL-3000data collection
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-05
    Type: Initial release
  • Version 1.1: 2014-11-12
    Changes: Other
  • Version 1.2: 2016-05-25
    Changes: Database references
  • Version 1.3: 2019-12-25
    Changes: Data collection, Database references, Derived calculations
  • Version 1.4: 2023-11-08
    Changes: Data collection, Database references, Derived calculations, Refinement description