Banca de DEFESA: JOÃO PAULO DE FREITAS NUNES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: JOÃO PAULO DE FREITAS NUNES
DATA: 28/07/2015
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich
TÍTULO:

Evolução e especialização funcional da Acil-CoA oxidase 4 em Viridiplantae

PALAVRAS-CHAVES:

ACX, beta oxidação, ACAD, filogenia molecular, família gênica.

PÁGINAS: 51
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
SUBÁREA: Química de Macromoléculas
ESPECIALIDADE: Proteínas
RESUMO:

Stored oils are essential to the germination and initial seedling establishment of oilseeds plants. After mobilization, these oils are subjected to β-oxidation in seed’s glyoxysomes, resulting Acetyl-CoA, which in turn feeds the Glyoxylate cycle. This cycle is a variation of the tricarboxylic acid cycle that uses acetyl-CoA to produce succinate or oxaloacetate molecules that can be later utilized in carbohydrate biosynthesis to support embryo development. The first step of glyoxysomal β-oxidation is catalyzed by a specific isoform of Acyl-CoA oxidase enzyme (ACX4), a member of the protein superfamily ACAD, which occurs more commonly in germinating seeds. However, five other ACX isoforms are found in plant genomes to date, each one related to specialized functions or fatty acid chain’s sizes. In order to understand the molecular evolutionary events underlying the functional specialization of these enzymes, we analyzed DNA, mRNA and protein sequences obtained in databases (NCBI, UNIPROT, TAIR, CDD, etc.) by bioinformatic inferences, to recognize and compare the introns-exons regions, as well as protein domains of different ACX isoforms from Viridiplantae species. Then the sequences were aligned, the Cis elements of the genes and their exon/domain, secondary structures were compared, submitted to structural modeling and maximum likelihood phylogenetic inferences. It was shown that the ACX4 enzymes are more closer related to other members of the ACAD superfamily, one of them the Acyl-CoA dehydrogenase enzyme (ACDH). Since fatty acids are not commonly used in other plants tissues to energy production and also β-oxidation by ACDH in mitochondria is more related to ATP synthesis, we hypothesized that ACX4 isoform may have been subjected to specific selective pressures, which stabilized its role during seed oil metabolism.

MEMBROS DA BANCA:
Externo à Instituição - CÍNTIA RENATA COSTA ROCHA - UFPE
Interno - 1880243 - DANIEL CARLOS FERREIRA LANZA
Presidente - 1513597 - JOAO PAULO MATOS SANTOS LIMA