IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Electron donors for the D5- acyl-lipid desaturase in Bacillus subtilis.
Autor/es:
CHAZARRETA-CIFRE, LORENA; DE MENDOZA, D; ALTABE, SILVIA GRACIELA
Lugar:
Villa CARlos Paz, Córdoba, Argentina
Reunión:
Congreso; XLIV Reuniòn Anual de SAIB.; 2008
Institución organizadora:
SAIB
Resumen:
Unsaturated fatty acids (UFAs) synthesis is carried out by desaturases. The reaction requires oxygen and utilizes NAD(P)H and flavoproteins as electron donors. The electron transport system of the D5-acyl lipid desaturase from B. subtilis has not been yet characterized. We have demonstrated that mutants in ferredoxin are not impaired in UFAs synthesis. The “in silico” analysis of the genome of B. subtilis reveals the existence of two flavodoxins YkuN and YkuP, and we propose that they could act as putative electron donors for the D5-desaturase. We constructed conditional mutants in the ykuNOP operon and the effect of the mutation on UFAs synthesis was evaluated after labeling the fatty acids with [14C]-palmitate followed by TLC. The results showed that absence of flavodoxins did not causes differences in the UFAs levels compared to the wild type strain. In order to verify our model that flavodoxins can act as electron donors for the D5-desaturase we constructed mutants in both, the ykuNOP operon and fer gene and evaluated the UFAs production. The results revealed that in B. subtilis the function of de D5-desaturase is impeded when both, ferredoxin and flavodoxins are absent. When flavodoxin is present in absence of ferredoxin, the results showed UFAs production. These experiments indicate that both flavoproteins can act as electron donors for UFAs synthesis in B. subtilis.