Probing the equatorial groove of the hookworm protein and vaccine candidate antigen, Na-ASP-2

Lyndel Mason, Leon Tribolet, Anne Simon, Natascha von Gnielinski, Lisa Nienaber, Paul Taylor, Charlene Willis, Malcolm K. Jones, Paul W. Sternberg, Robin B. Gasser, Alex Loukas*, Andreas Hofmann

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Hookworm activation-associated secreted proteins can be structurally classified into at least three different groups. The hallmark feature of Group 1 activation-associated secreted proteins is a prominent equatorial groove, which is inferred to form a ligand binding site. Furthermore, a conserved tandem histidine motif is located in the centre of the groove and believed to provide or support a yet to be determined catalytic activity.

Here, we report three-dimensional crystal structures of Na-ASP-2, an L3-secreted activation-associated secreted protein from the human hookworm Necator americanus, which demonstrate transition metal binding ability of the conserved tandem histidine motif. We further identified moderate phosphohydrolase activity of recombinant Na-ASP-2, which relates to the tandem histidine motif. By panning a random 12-mer peptide phage library, we identified a peptide with high similarity to the human calcium-activated potassium channel SK3, and confirm binding of the synthetic peptide to recombinant Na-ASP-2 by differential scanning fluorimetry. Potential binding modes of the peptide to Na-ASP-2 were studied by molecular dynamics simulations which clearly identify a preferred topology of the Na-ASP-2:SK3 peptide complex. (C) 2014 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)146-155
Number of pages10
JournalInternational Journal of Biochemistry and Cell Biology
Publication statusPublished - 13 May 2014


  • activation-associated secreted proteins
  • host-parasite interactions
  • pathogenesis-related proteins
  • protein structure
  • SCP/TAPS proteins
  • CA2+-activated K+ channels
  • activated potassium channels
  • rich secretory proteins
  • x-ray-structure
  • small-conductance
  • necator-americanus
  • biochemical-characterization
  • SK3 channel
  • in-vitro
  • superfamily

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