Caracterização bioquímica da aldeído desidrogenase GmTP55 da soja (Glycine max)

• Ano de defesa: 2007
• Autor(a) principal: Soares, Ana Paula Gomes
• Orientador(a): Fontes, Elizabeth Pacheco Batista
• Banca de defesa: Fietto, Juliana Lopes Rangel , Moraes, George Henrique Kling de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Bioquímica Agrícola
• Departamento: Bioquímica e Biologia molecular de plantas; Bioquímica e Biologia molecular animal
• País: BR
• Palavras-chave em Português: Aldeído desidrogenase; Glycine max; Soja
• Palavras-chave em Inglês: Aldehyde dehydrogenase; Glycine max; Soybean
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR
• Link de acesso: http://locus.ufv.br/handle/123456789/2477

The protein GmTP55 (Glycine max turgor proten) belongs to the ALDH7 family, that falls into the superfamily of the aldehyde dehydrogenases (ALDH). Proteins of this family are structurally conserved and they have been identified by their accumulation in plants under abiotic stress conditions. Although they have been identified in several organisms, the physiological and biochemical function of proteins of the ALDH7 family have not been elucidated yet. In addition to sharing a high conservation of primary structure with other members of ALDH family, GmTP55 possesses several conserved domains and conserved amino acid at common positions of aldehyde dehydrogenases. To identify the biochemical function of the protein GmTP55, we expressed the protein in a prokaryotic expression system, and the enzymatic activity of the recombinant protein was tested using several aldehydes, as potential substrates. The protein GmTP55 exhibited a larger specificity for short-chain aliphatic aldehydes, as propionaldehyde, acetaldehyde, γ-aminobutiraldehyde and formaldehyde, oxidizing the carboxylic acids, in the presence of NAD+. Among the oxidized aldehydes, γ-aminobutiraldeido and formaldehyde may be considered as potential physiological substrates for GmTP55, as these aldehydes are produced as a result of the lipid peroxidation that occurs during the imposition of salt stress. The analysis of the physiological function of the protein GmTP55 was accomplished by using Arabidopsis thaliana plants ectopically expressing GmTP55 gene. Under conditions of salt stress, the seeds of transgenic plants exhibited a greater germination efficiency than the untransformed plants. Taken together, these results suggest that the protein GmTP55 is involved in plant tolerance to abiotic stresses and it acts in detoxification pathways of reactive aldehydes derived from lipid peroxidation.