Ancylostoma ceylanicum excretory-secretory protein 2 adopts a netrin-like fold and defines a novel family of nematode proteins.
Publication Type:Journal Article
Source:J Mol Biol, Volume 408, Issue 1, p.9-17 (2011)
Keywords:Amino Acid Sequence, Ancylostoma, Ancylostomatoidea, Ancylostomiasis, Animals, Complement System Proteins, Helminth Proteins, Humans, Matrix Metalloproteinases, Molecular Sequence Data, Nerve Growth Factors, Netrin-1, Protein Conformation, Protein Folding, Sequence Homology, Amino Acid, Tissue Inhibitor of Metalloproteinases, Tumor Suppressor Proteins
<p>Hookworms are human parasites that have devastating effects on global health, particularly in underdeveloped countries. Ancylostoma ceylanicum infects humans and animals, making it a useful model organism to study disease pathogenesis. A. ceylanicum excretory-secretory protein 2 (AceES-2), a highly immunoreactive molecule secreted by adult worms at the site of intestinal attachment, is partially protective when administered as a mucosal vaccine against hookworm anemia. The crystal structure of AceES-2 determined at 1.75 Å resolution shows that it adopts a netrin-like fold similar to that found in tissue inhibitors of matrix metalloproteases (TIMPs) and in complement factors C3 and C5. However, recombinant AceES-2 does not significantly inhibit the 10 most abundant human matrix metalloproteases or complement-mediated cell lysis. The presence of a highly acidic surface on AceES-2 suggests that it may function as a cytokine decoy receptor. Several small nematode proteins that have been annotated as TIMPs or netrin-domain-containing proteins display sequence homology in structurally important regions of AceES-2's netrin-like fold. Together, our results suggest that AceES-2 defines a novel family of nematode netrin-like proteins, which may function to modulate the host immune response to hookworm and other parasites.</p>