Crystal Structure Analysis of Ostertagia ostertagi ASP-1

Experimental Data Snapshot

  • Resolution: 1.85 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.192 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Structure of Ostertagia ostertagi ASP-1: insights into disulfide-mediated cyclization and dimerization

Borloo, J.Geldhof, P.Peelaers, I.Van Meulder, F.Ameloot, P.Callewaert, N.Vercruysse, J.Claerebout, E.Strelkov, S.V.Weeks, S.D.

(2013) Acta Crystallogr D Biol Crystallogr 69: 493-503

  • DOI: https://doi.org/10.1107/S0907444912050019
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The cysteine-rich secretory/antigen 5/pathogenesis-related 1 (CAP) protein superfamily is composed of a functionally diverse group of members that are found in both eukaryotes and prokaryotes. The excretome/secretome of numerous helminths (parasitic nematodes) contains abundant amounts of CAP members termed activation-associated secreted proteins (ASPs). Although ASPs are necessary for the parasitic life cycle in the host, the current lack of structural and functional information limits both understanding of their actual role in host-parasite interactions and the development of new routes in controlling parasitic infections and diseases. Alleviating this knowledge gap, a 1.85 Å resolution structure of recombinantly produced Oo-ASP-1 from Ostertagia ostertagi, which is one of the most prevalent gastrointestinal parasites in cattle worldwide, was solved. Overall, Oo-ASP-1 displays the common hallmark architecture shared by all CAP-superfamily members, including the N-terminal CAP and C-terminal cysteine-rich domains, but it also reveals a number of highly peculiar features. In agreement with studies of the natively produced protein, the crystal structure shows that Oo-ASP-1 forms a stable dimer that has been found to be primarily maintained via an intermolecular disulfide bridge, hence the small interaction surface of only 306.8 Å(2). Moreover, unlike any other ASP described to date, an additional intramolecular disulfide bridge links the N- and C-termini of each monomer, thereby yielding a quasi-cyclic molecule. Taken together, the insights presented here form an initial step towards a better understanding of the actual biological role(s) that this ASP plays in host-parasite interactions. The structure is also essential to help to define the key regions of the protein suitable for development of ASP-based vaccines, which would enable the current issues surrounding anthelmintic resistance in the treatment of parasitic infections and diseases to be circumvented.

  • Organizational Affiliation

    Laboratory of Parasitology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium. jimmy.borloo@ugent.be

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ancylostoma-secreted protein-like protein
A, B
219Ostertagia ostertagiMutation(s): 0 
Gene Names: ASP-1OSP-2
Find proteins for Q8T8F4 (Ostertagia ostertagi)
Explore Q8T8F4 
Go to UniProtKB:  Q8T8F4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8T8F4
Glycosylation Sites: 1
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on NAG

Download Ideal Coordinates CCD File 
D [auth B]2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
Query on SO4

Download Ideal Coordinates CCD File 
O4 S
Experimental Data & Validation

Experimental Data

  • Resolution: 1.85 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.192 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 75.178α = 90
b = 76.291β = 90
c = 81.529γ = 90
Software Package:
Software NamePurpose
SCALAdata scaling
PDB_EXTRACTdata extraction
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-03-27
    Type: Initial release
  • Version 1.1: 2013-08-07
    Changes: Database references
  • Version 1.2: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Database references, Derived calculations, Structure summary
  • Version 1.3: 2023-11-08
    Changes: Data collection, Database references, Refinement description, Structure summary