title: Digestive peptidase evolution in holometabolous insects led to a divergent group of enzymes in Lepidoptera.
abstract: Trypsins and chymotrypsins are well-studied serine peptidases that cleave peptide bonds at the carboxyl side of basic and hydrophobic L-amino acids, respectively. These enzymes are largely responsible for the digestion of proteins. Three primary processes regulate the activity of these peptidases: secretion, precursor (zymogen) activation and substrate-binding site recognition. Here, we present a detailed phylogenetic analysis of trypsins and chymotrypsins in three orders of holometabolous insects and reveal divergent characteristics of Lepidoptera enzymes in comparison with those of Coleoptera and Diptera. In particular, trypsin subsite S1 was more hydrophilic in Lepidoptera than in Coleoptera and Diptera, whereas subsites S2-S4 were more hydrophobic, suggesting different substrate preferences. Furthermore, Lepidoptera displayed a lineage-specific trypsin group belonging only to the Noctuidae family. Evidence for facilitated trypsin auto-activation events were also observed in all the insect orders studied, with the characteristic zymogen activation motif complementary to the trypsin active site. In contrast, insect chymotrypsins did not seem to have a peculiar evolutionary history with respect to their mammal counterparts. Overall, our findings suggest that the need for fast digestion allowed holometabolous insects to evolve divergent groups of peptidases with high auto-activation rates, and highlight that the evolution of trypsins led to a most diverse group of enzymes in Lepidoptera.
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Av. Pádua Dias, 11, 13418-900 Piracicaba, SP, Brazil.
authors.forename: Renata O
authors.initials: RO
authors.lastname: Dias
authors.affiliation: Department of Physics and Istituto Pasteur, Fondazione Cenci Bolognetti, Sapienza University, P.le A. Moro, 5, 00185 Rome, Italy.
authors.forename: Allegra
authors.initials: A
authors.lastname: Via
authors.affiliation: Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Cândido Rondon, 400, 13083-875 Campinas, SP, Brazil.
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Brandão
authors.affiliation: Department of Physics and Istituto Pasteur, Fondazione Cenci Bolognetti, Sapienza University, P.le A. Moro, 5, 00185 Rome, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Tramontano
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Av. Pádua Dias, 11, 13418-900 Piracicaba, SP, Brazil. Electronic address: mdcsilva@usp.br.
authors.forename: Marcio C
authors.initials: MC
authors.lastname: Silva-Filho
mesh_terms: D000818:Animals; D001665:Binding Sites; D005075:Biological Evolution; D002918:Chymotrypsin / Q000737:chemistry / Q000378:metabolism*; D001517:Coleoptera / Q000201:enzymology; D004175:Diptera / Q000201:enzymology; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism; D007313:Insecta / Q000201:enzymology*; D007915:Lepidoptera / Q000201:enzymology; D010447:Peptide Hydrolases / Q000737:chemistry; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D014357:Trypsin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D010447:Peptide Hydrolases; D002918:Chymotrypsin; D014357:Trypsin
keywords: Chymotrypsin; Coleoptera; Diptera; Lepidoptera; Serine peptidase; Trypsin