Caracterização da diversidade molecular de venenos das serpentes brasileiras Bothrops cotiara e Crotalus durissus terrificus
Arquivos
Data
2023-10-25
Autores
Miyamoto, Jackson Gabriel 
Orientadores
Tashima, Alexandre Keiji
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A variabilidade composicional das peçonhas de serpentes retrata a evolução toxinológica e a adaptação a diferentes nichos ecológicos. Essa variabilidade tem sido observada em relação a diferentes fatores, como idade, dieta, gênero, sazonalidade, e distribuição geográfica. As grandes famílias de toxinas reproduzem a diversificação por meio de adaptação evolutiva, neo-funcionalização e retenção de múltiplos genes parálogos, manifestando-se como variações quantitativas e qualitativas. Em oposição a alterações arbitrárias, a diversificação composicional aparenta ser inerente às estruturas biológicas. No intuito de se investigar a variabilidade e diversidade da peçonha de duas serpentes brasileiras, o repertório de toxinas foi avaliado através das abordagens peptidômica e proteômica. No Capítulo 1, diversos novos peptídeos foram caracterizados por análise peptidômica no veneno da serpente Bothrops cotiara. Dentre os peptídeos identificados, um novo fragmento críptico de uma metaloproteinase apresentou inibição da enzima conversora de angiotensina (ECA), com constantes de inibição abaixo de 1 µM. Este inibidor não canônico da ECA não atende ao consenso estrutural de peptídeos potenciadores de bradicinina de serpentes, e apresenta semelhanças estruturais com a bradicinina e peptídeos relacionados à bradicinina. Desta forma, os resultados contribuem para o repertório de peptídeos biologicamente ativos derivados de venenos de serpentes capazes de inibir a ECA para além das estruturas e precursores conhecidos. No Capítulo 2 foi realizada uma análise abrangente da peçonha de Crotalus durissus terrificus, revelando mutações e dimorfismo sexual em níveis peptidômico e proteômico. A análise de mutações revelou novas toxinas com alinhamento estrutural predito condizente com estruturas homólogas/parálogas determinadas experimentalmente. Uma vez que as variações de resíduos não ocorreram em aminoácidos centrais de interação das toxinas, os resultados sugerem que as mutações observadas podem não impactar significativamente a estabilidade e funções dessas proteínas, sugerindo a conservação estrutural de toxinas evolutivamente relacionadas. O conhecimento acerca da diversidade toxinológica pode contribuir com o avanço no tratamento adequado de acidentes ofídicos, e consequentemente, para o combate dessa doença tropical negligenciada, bem como pode fundamentar o desenvolvimento de novos fármacos através da prospecção destas vastas bibliotecas de toxinas.
The compositional variability of snake venom depicts a dynamic representation of toxinological evolution to adapt to different ecological niches. This variability has been reported at several levels, such as age, gender, seasonality, geographic, dietary, interfamily, intergenus, and intraspecies. The large families of toxins reproduce diversification through evolutionary adaptation, neofunctionalization, and retention of multiple paralogous genes, manifesting itself as a natural quantitative and qualitative variation. Rather than arbitrary deviations, compositional diversification appears to be inherent within specimens’ biological framework. To investigate venom diversity and variability of two Brazilian snakes, the toxin repertoire was assessed through peptidomic and proteomic approach. In chapter 1, several peptides were characterized through peptidomic analysis of Bothrops cotiara snake venom. Among the identified peptides, a novel cryptide fragment of a metalloproteinase was capable of inhibiting angiotensin converting enzyme (ACE), with inhibition constants below 1 µM. This non-canonical ACE inhibitor presented structural similarities do bradykinin and bradykinin-related peptides and did not fulfill the primary structure consensus of bradykinin potentiating peptides, thus contributing to the repertoire of biologically active peptides capable of inhibiting ACE beyond the current known motifs and precursors. In chapter 2 a comprehensive analysis of Crotalus durissus terrificus venom was performed, uncovering sexual dimorphism at both peptidomic and protemic levels. Furthermore, mutation analysis unraveled novel toxins with consistent structural alignment to homologous/paralogous experimentally determined structures. As mutational variants were not detected in key contact residues of venom toxins, these results suggest that the observed mutations may not significantly impact the overall stability and toxic activities of these proteins, underscoring the conservation of structural features in evolutionary related toxins. The knowledge regarding toxinological diversity represents a critical advance in the proper treatment of snakebites, making substantial contributions to addressing the burden of this neglected tropical disease, as well as underpins the potential for drug development through bioprospecting these vast toxins libraries.
The compositional variability of snake venom depicts a dynamic representation of toxinological evolution to adapt to different ecological niches. This variability has been reported at several levels, such as age, gender, seasonality, geographic, dietary, interfamily, intergenus, and intraspecies. The large families of toxins reproduce diversification through evolutionary adaptation, neofunctionalization, and retention of multiple paralogous genes, manifesting itself as a natural quantitative and qualitative variation. Rather than arbitrary deviations, compositional diversification appears to be inherent within specimens’ biological framework. To investigate venom diversity and variability of two Brazilian snakes, the toxin repertoire was assessed through peptidomic and proteomic approach. In chapter 1, several peptides were characterized through peptidomic analysis of Bothrops cotiara snake venom. Among the identified peptides, a novel cryptide fragment of a metalloproteinase was capable of inhibiting angiotensin converting enzyme (ACE), with inhibition constants below 1 µM. This non-canonical ACE inhibitor presented structural similarities do bradykinin and bradykinin-related peptides and did not fulfill the primary structure consensus of bradykinin potentiating peptides, thus contributing to the repertoire of biologically active peptides capable of inhibiting ACE beyond the current known motifs and precursors. In chapter 2 a comprehensive analysis of Crotalus durissus terrificus venom was performed, uncovering sexual dimorphism at both peptidomic and protemic levels. Furthermore, mutation analysis unraveled novel toxins with consistent structural alignment to homologous/paralogous experimentally determined structures. As mutational variants were not detected in key contact residues of venom toxins, these results suggest that the observed mutations may not significantly impact the overall stability and toxic activities of these proteins, underscoring the conservation of structural features in evolutionary related toxins. The knowledge regarding toxinological diversity represents a critical advance in the proper treatment of snakebites, making substantial contributions to addressing the burden of this neglected tropical disease, as well as underpins the potential for drug development through bioprospecting these vast toxins libraries.