Novel X-Ray Structure of Na-ASP-2, a PR-1 protein from the nematode parasite Necator americanus and a vaccine antigen for human hookworm infection

Experimental Data Snapshot

  • Resolution: 1.56 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.178 

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X-ray structure of Na-ASP-2, a pathogenesis-related-1 protein from the nematode parasite, Necator americanus, and a vaccine antigen for human hookworm infection.

Asojo, O.A.Goud, G.Dhar, K.Loukas, A.Zhan, B.Deumic, V.Liu, S.Borgstahl, G.E.Hotez, P.J.

(2005) J Mol Biol 346: 801-814

  • DOI: https://doi.org/10.1016/j.jmb.2004.12.023
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Human hookworm infection is a major cause of anemia and malnutrition of adults and children in the developing world. As part of on-going efforts to control hookworm infection, The Human Hookworm Vaccine Initiative has identified candidate vaccine antigens from the infective L3 larval stages of the parasite, including a family of pathogenesis-related (PR) proteins known as the Ancylostoma-secreted proteins (ASPs). A novel crystal structure of Na-ASP-2, a PR-1 protein secreted by infective larvae of the human hookworm Necator americanus, has been solved to resolution limits of 1.68 A and to an R-factor of 17% using the recombinant protein expressed in and secreted by Pichia pastoris. The overall fold of Na-ASP-2 is a three-layer alphabetaalpha sandwich flanked by an N-terminal loop and a short, cysteine-rich C terminus. Our structure reveals a large central cavity that is flanked by His129 and Glu106, two residues that are well conserved in all parasitic nematode L3 ASPs. Na-ASP-2 has structural and charge similarities to chemokines, which suggests that Na-ASP-2 may be an extra-cellular ligand of an unknown receptor. Na-ASP-2 is a useful homology model for NIF, a natural antagonistic ligand of CR3 receptor. From these modeling studies, possible binding modes were predicted. In addition, this first structure of a PR-1 protein from parasitic helminths may shed light on the molecular basis of host-parasite interactions.

  • Organizational Affiliation

    Eppley Institute for Research in Cancer and Allied Diseases, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA. oasojo@unmc.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
secreted protein ASP-2196Necator americanusMutation(s): 0 
Find proteins for Q7Z1H1 (Necator americanus)
Explore Q7Z1H1 
Go to UniProtKB:  Q7Z1H1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7Z1H1
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.56 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.178 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 37.89α = 90
b = 51.54β = 114.06
c = 43.63γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-02-01
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description