Molecular and biochemical analysis of an aspartylglucosaminidase from the venom of the parasitoid wasp Asobara tabida (Hymenoptera: Braconidae).
The most abundant venom protein of the parasitoid wasp Asobara tabida was identified to be an aspartylglucosaminidase (hereafter named AtAGA). The aim of the present work is the identification of: 1) its cDNA and deduced amino acid sequences, 2) its subunits organization and 3) its activity. The cDNA of AtAGA coded for a proalphabeta precursor molecule preceded by a signal peptide of 19 amino acids. The gene products were detected specifically in the wasp venom gland (in which it could be found) under two forms: an (active) heterotetramer composed of two alpha and two beta subunits of 30 and 18 kDa respectively and a homodimer of 44 kDa precursor. The activity of AtAGA enzyme showed a limited tolerance toward variations of pH and temperatures. Since the enzyme failed to exhibit any glycopeptide N-glycosidase activity toward entire glycoproteins, its activity seemed to be restricted to the deglycosylation of free glycosylasparagines like human AGA, indicating AtAGA did not evolve a broader function in the course of evolution. The study of this enzyme may allow a better understanding of the functional evolution of venom enzymes in hymenopteran parasitoids.
Vinchon
S
S
Laboratoire de Biologie des Entomophages, EA3900 BioPI, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex, France. sophie.vinchon@u-picardie.fr
Moreau
S J M
SJ
Drezen
J M
JM
Prévost
G
G
Cherqui
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001227:Aspartylglucosylaminase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004795:Enzyme Stability; D019143:Evolution, Molecular; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014862:Wasp Venoms / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D014863:Wasps / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
D019476:Insect Proteins; D021122:Protein Subunits; D014862:Wasp Venoms; D001227:Aspartylglucosylaminase