Caracterização do mecanismo catalítico da SGP, enzima protótipo das glutâmico peptidases

• Ano de defesa: 2012
• Autor(a) principal: Kondo, Marcia Yuri [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Especificidade; Mecanismo catalítico; Glutâmico peptidases; Ácido glutâmico; Peptídeo hidrolases; Domínio catalítico; Sensibilidade e especificidade
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9174

Proteolytic enzymes are widespread in all organisms and are involved in a wide range of biological roles. There are seven distinct classes of proteases (serine, cysteine, aspartate, metalloproteases, threonine, glutamate and the newly identified asparagine peptide lyases), grouped according to their catalytic mechanism. The glutamic peptidases are carboxylic (acidic) proteases insensitive to pepstatin inhibitor and were annotated as a new group in 2004 (Family G1 Merops). These proteases have a unique catalytic dyad of residues Glu and Gln and a previously undescribed structure fold. Scytalidoglutamic peptidase (SGP), isolated from the wood-degrading fungus Scytalidium lignicolum on the 1970’s, is the forming member of glutamic peptidases. The three dimensional structures of scytalidoglutamic peptidase (SGP) and aspergilloglutamic peptidase (AGP) from Aspergillus niger revealed that the overall structure of these enzymes are almost identical, however two different catalytic mechanisms were proposed. Aiming at understanding the reaction mechanism of glutamic peptidases, in this thesis the following topics are highlighted, (1) biochemical characterization of the catalytic mechanism of SGP by use of pH rates profiles and solvent kinetic isotopic effects (SKIE) on the enzyme hydrolysis of FRET peptides and (2) specificity of the protease for P1 and P1’ positions describing the interactions of S1 subsite during catalysis. The paper showing results of these studies is attached to this thesis (Kondo, MY et al, JBC 2010).