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| Author(s): |
Renata de Oliveira Dias
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2014-08-07 |
| Examining board members: |
Marcio de Castro Silva Filho;
Octávio Luiz Franco;
Flávio Henrique da Silva;
Walter Ribeiro Terra;
Claudia Barros Monteiro Vitorello
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| Advisor: | Marcio de Castro Silva Filho |
| Abstract | |
Trypsins and chymotrypsins are well-studied classes of serine peptidases largely responsible for the digestion of proteins by cleavage of the peptide bond at the carboxyl side of basic and hydrophobic L-amino acids, respectively. Three processes mainly regulate the action of these peptidases: secretion, precursor (zymogen) activation and substrate-binding site recognition. In the present work is presented a detailed phylogenetic analysis of trypsins and chymotrypsins in three orders of holometabolous insects revealing divergent characteristics in the Lepidoptera enzymes in relation to Coleoptera and Diptera. In particular, trypsin subsite S1 was observed to be more hydrophilic in Lepidoptera than in Coleoptera and Diptera, whereas subsites S2-S4 appeared more hydrophobic, suggesting different substrate preferences. Furthermore, Lepidoptera displayed a very specific taxonomic trypsin group, only encompassing proteins from the Noctuidae family. Evidences for facilitated trypsin auto-activation events were also observed in all the insect orders at hand, 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 e.g. their mammal counterparts. Overall, the present findings suggest that the need for fast digestion made holometabolous insects evolve specialized groups of trypsins with high autoactivation rates and highlight that the evolution of trypsins culminated in a specialized group of enzymes in Lepidoptera. (AU) | |
| FAPESP's process: | 10/17110-5 - Characterization of molecular bases involved in the polifagism of herbivore insect |
| Grantee: | Renata de Oliveira Dias |
| Support Opportunities: | Scholarships in Brazil - Doctorate |