title: Identification of an aspartylglucosaminidase-like protein in the venom of the parasitic wasp Asobara tabida (Hymenoptera: Braconidae).
abstract: This study was designed to identify one of the main components of venomous secretions of the endoparasitic wasp Asobara tabida. By using electrophoretic methods, partial amino acid sequencing and immunostaining, we demonstrated the presence of an aspartylglucosaminidase (AGA)-like protein in the venom of this insect. The enzyme had a polymeric conformation and was formed of 30 and 18 kDa subunits. The relative positions of several amino acids involved in substrate binding and catalytic activity of known AGA-proteins, which are usually lysosomal enzymes, were conserved in the NH(2)-terminal ends of these subunits. Antibodies raised against human AGA recognized the two subunits of the protein and a 44 kDa protein, suggesting the presence of a precursor molecule of the enzyme in the venom. However, no reliable measurement of the AGA activity could be performed on the venom extracts, which could be explained by the fact the enzyme would be stored in the reservoir of the venom apparatus under an inactive form. These results constitute the first description of an AGA-like protein in an insect venom and are discussed with respect to the knowledge acquired on lysosomal and venom enzymes.
authors.affiliation: Laboratoire de Biologie des Entomophages, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens cedex, France.
authors.forename: S J M
authors.initials: SJ
authors.lastname: Moreau
authors.forename: A
authors.initials: A
authors.lastname: Cherqui
authors.forename: G
authors.initials: G
authors.lastname: Doury
authors.forename: F
authors.initials: F
authors.lastname: Dubois
authors.forename: Y
authors.initials: Y
authors.lastname: Fourdrain
authors.forename: L
authors.initials: L
authors.lastname: Sabatier
authors.forename: P
authors.initials: P
authors.lastname: Bulet
authors.forename: J
authors.initials: J
authors.lastname: Saarela
authors.forename: G
authors.initials: G
authors.lastname: Prévost
authors.forename: P
authors.initials: P
authors.lastname: Giordanengo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001227:Aspartylglucosylaminase / Q000235:genetics*; D004331:Drosophila melanogaster / Q000469:parasitology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007124:Immunoenzyme Techniques; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D021122:Protein Subunits; D016415:Sequence Alignment; D013194:Staining and Labeling / Q000379:methods; D014862:Wasp Venoms / Q000737:chemistry / Q000201:enzymology*; D014863:Wasps / Q000201:enzymology*
chemical_list: D019476:Insect Proteins; D021122:Protein Subunits; D014862:Wasp Venoms; D001227:Aspartylglucosylaminase