Estudo da formação da friedelina a partir de mutações no gene da friedelina sintase

• Ano de defesa: 2015
• Autor(a) principal: Pinheiro, Karina Alves [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Espinheira santa; Mutagenese; Clonagem; Saccharomyces cerevisiae; Espectrometria de massa; Mass spectrometry
• Link de acesso: http://hdl.handle.net/11449/142999

The cloning of oxidosqualene cyclase from Maytenus ilicifolia leaves and expression in Saccharomyces cerevisiae has been studied by our group to generate friedelin. The main objective of this project was to carry out the expression of friedelin synthase gene using commercially Kalanchoe daigremontiana, whose sequence has been optimized according to the codon usage of S. cerevisiae. In such studies, two mutations in the synthetic gene were confirmed. The first mutation of valine for leucine residue at position 483 synthetic gene led to the production of friedelin, β-amyrin and tararexol, while the second mutation of leucine to threonine residue, at the same position, produced exclusively β-amyrin. The same mutations were performed using the gene of friedelin synthase of Maytenus ilicifolia. The compound identities were confirmed by gas chromatography and mass spectrometry. The results suggested that the ratio of protein production-enzyme function, involved in the production of friedelin, may be associated with the active cavity of the enzyme setting, when an amino acid residue of the active site is replaced for smaller, expanding the cavity to provide the prior stabilization of the carbocation in the biosynthetic pathway of triterpenes to produce β-amyrin. Thus, these data contribute to understand the specificity of such enzyme. Furthemore, this studie was the first one to show the importance of each amino acid in the active site of the enzyme to produce a pentacyclic triterpene with the highest number of rearrangements and was the basis for future studies of enzyme engeenering to increase productivity of such compounds.