Cloning and characterization of trypsin- and chymotrypsin-like proteases from the midgut of the sand fly vector Phlebotomus papatasi
Autor(es): Ramalho-Ortigao, JM; Kamhawi, S; Rowton, ED; Ribeiro, JMC; Valenzuela, JG
Resumo: Trypsin and chymotrypsin serine proteases are the main digestive proteases in Diptera midguts and are also involved in many aspects of the vector-parasite relationship. In sand flies, these proteases have been shown to be a potential barrier to Leishmania growth and development within the midgut. Here we describe the sequence and partial characterization of six Phlebotomus papatasi midgut serine proteases: two chymotrypsin-like (Ppchym1 and Ppchym2) and four trypsin-like (Pptryp1-Pptryp4). All six enzymes show structural features typical to each type, including the histidine, aspartic acid, and serine (H/D/S) catalytic triad, six conserved cysteine residues, and other amino acid residues involved in substrate specificity. They also show a high degree of homology (4060% identical residues) with their counterparts from other insect vectors, such as Anopheles gambiae and Aedes aegypti. The mRNA expression profiles of these six proteases vary considerably: two trypsin-like proteases (Pptryp1 and Pptryp2) are downregulated and one (Pptryp4) upregulated upon blood feeding. The two chymotrypsin-like enzymes display expression behavior similar to that of the early and late trypsins from Ae. aegypti. Published by Elsevier Science Ltd.
Palavras-Chave: Sand flies; Midgut trypsin; Chymotrypsin - like proteases; RT-PCR
Imprenta: Insect Biochemistry and Molecular Biology, v. 33, n. 2, p. 163-171, 2003
Identificador do objeto digital: 10.1016/S0965-1748(02)00187-X
Descritores: Aedes aegypti - RT-PCR ; Aedes aegypti - Public health
Data de publicação: 2003
