Dias Renata O, Via Allegra, Brandão Marcelo M, Tramontano Anna, Silva-Filho Marcio C
Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Av. Pádua Dias, 11, 13418-900 Piracicaba, SP, Brazil.
Department of Physics and Istituto Pasteur, Fondazione Cenci Bolognetti, Sapienza University, P.le A. Moro, 5, 00185 Rome, Italy.
Insect Biochem Mol Biol. 2015 Mar;58:1-11. doi: 10.1016/j.ibmb.2014.12.009. Epub 2015 Jan 17.
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.
胰蛋白酶和胰凝乳蛋白酶是经过充分研究的丝氨酸肽酶，它们分别在碱性和疏水性L-氨基酸的羧基侧切割肽键。这些酶在很大程度上负责蛋白质的消化。有三个主要过程调节这些肽酶的活性：分泌、前体（酶原）激活和底物结合位点识别。在此，我们对全变态昆虫三个目的胰蛋白酶和胰凝乳蛋白酶进行了详细的系统发育分析，并揭示了鳞翅目昆虫的酶与鞘翅目和双翅目昆虫的酶相比具有不同的特征。特别是，鳞翅目昆虫的胰蛋白酶亚位点S1比鞘翅目和双翅目昆虫的更具亲水性，而亚位点S2 - S4更具疏水性，这表明底物偏好不同。此外，鳞翅目显示出一个仅属于夜蛾科的谱系特异性胰蛋白酶组。在所有研究的昆虫目中也观察到了促进胰蛋白酶自激活事件的证据，其特征性的酶原激活基序与胰蛋白酶活性位点互补。相比之下，昆虫的胰凝乳蛋白酶与其哺乳动物对应物相比似乎没有特殊的进化历史。总体而言，我们的研究结果表明，快速消化的需求使得全变态昆虫进化出具有高自激活率的不同肽酶组，并强调胰蛋白酶的进化导致鳞翅目中一组最多样化的酶。
