title: Identification and characterization of onchoastacin, an astacin-like metalloproteinase from the filaria Onchocerca volvulus.
abstract: The tissue-invasive nematode Onchocerca volvulus causes skin and eye pathology in human onchocerciasis. While the adult females reside sessile in subcutaneous nodules, the microfilariae are abundantly released from the nodules, males and juvenile worms migrate through the host tissue. Matrix-degrading metallo- and serine proteinases have been detected in excretory-secretory worm products that may be essential for migration of the mobile stages. In this study, a 1713bp long cDNA encoding for a putative proteinase of O. volvulus has been isolated. The predicted protein sequence includes a signal peptide indicating secretion to the extracellular space, a propeptide, an astacin-like protease domain, an EGF-like and a CUB-domain, thereby identifying the protein as a member of the astacin family of zinc endopeptidases. Onchoastacin, Ov-AST-1, is most closely related to a subfamily comprising nematode astacins including Caenorhabditis and Ancylostoma. Ov-AST-1 was expressed as a recombinant protein in baculovirus-infected insect cells and exhibited enzymatic activity. The exposure of onchoastacin to the host immune system is indicated by demonstration of IgG reacting with the recombinant Ov-AST-1 and with two peptides of the protein. Since a homologous metalloproteinase is part of a promising hookworm vaccine, Ov-AST-1 may be a candidate for intervention strategies in filarial infections.
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Borchert
authors.forename: Christoph
authors.initials: C
authors.lastname: Becker-Pauly
authors.forename: Antje
authors.initials: A
authors.lastname: Wagner
authors.forename: Peter
authors.initials: P
authors.lastname: Fischer
authors.forename: Walter
authors.initials: W
authors.lastname: Stöcker
authors.forename: Norbert W
authors.initials: NW
authors.lastname: Brattig
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006801:Humans; D008666:Metalloendopeptidases / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D017181:Onchocerca volvulus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D009855:Onchocerciasis / Q000469:parasitology; D010802:Phylogeny
chemical_list: D008666:Metalloendopeptidases; C071288:astacin