Biochemical and antigenic characterization of a new dipeptidyl-peptidase isolated from Aspergillus fumigatus.
A novel dipeptidyl-peptidase (DPP V) was purified from the culture medium of Aspergillus fumigatus. This is the first report of a secreted dipeptidyl-peptidase. The enzyme had a molecular mass of 88 kDa and contained approximately 9 kDa of N-linked carbohydrate. The expression and secretion of dipeptidyl-peptidase varied with the growth conditions; maximal intra- and extracellular levels were detected when the culture medium contained only proteins or protein hydrolysates in the absence of sugars. The gene of DPP V was cloned and showed significant sequence homology to other eukaryotic dipeptidyl-peptidase genes. Unlike the other dipeptidyl-peptidases, which are all intracellular, DPP V contained a signal peptide. Like the genes of other dipeptidyl-peptidases, that of DPP V displayed the consensus sequences of the catalytic site of the nonclassical serine proteases. The biochemical properties of native and recombinant DPP V obtained in Pichia pastoris were unique and were characterized by a substrate specificity limited to the hydrolysis of X-Ala, His-Ser, and Ser-Tyr dipeptides at a neutral pH optimum. In addition, we showed that DPP V is identical to one of the two major antigens used for the diagnosis of aspergillosis.
Beauvais
A
A
Laboratoire des Aspergillus, Institut Pasteur, Paris, France.
Monod
M
M
Debeaupuis
J P
JP
Diaquin
M
M
Kobayashi
H
H
Latgé
J P
JP
D000595:Amino Acid Sequence; D000946:Antigens, Fungal / Q000737:chemistry*; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000276:immunology; D003001:Cloning, Molecular; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000276:immunology; D005800:Genes, Fungal; D006023:Glycoproteins / Q000737:chemistry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D000946:Antigens, Fungal; D006023:Glycoproteins; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases