IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
. “New Insights on Protein Lipoylation Pathways in Bacillus subtilis”
Autor/es:
NATALIA MARTIN; DIEGO DE MENDOZA; MARÍA CECILIA MANSILLA
Lugar:
Carlos Paz, Argentina
Reunión:
Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008
Resumen:
Lipoic acid (LA), a covalently bound cofactor, is essential for the function of several key enzymes involved in oxidative metabolism. The model for protein lipoylation in E. coli involves two pathways: one in which exogenous LA is transferred to apoproteins in a process mediated by LA ligase (LplA), and an endogenous one, that involves LipB, which transfers octanoate to target proteins. These octanoylated domains are converted into lipoylated derivatives by lipoyl synthase (LipA). We have previously demonstrated that LipL is essential for the endogenous lipoylation pathway in Bacillus subtilis. Besides, this organism has two ORFs that encode products homologous to LplAs (yhfJ and yqhM). Since YqhM is homologous to an exogenous ligase, no growth or sporulation defects would be expected in an yqhM mutant. Surprisingly, such mutant was impaired to grow in minimal media. Its growth was restored by adding LA or the products of the lipoylated enzymes. This strain also showed a different membrane lipid composition than the observed in the wild type. In addition, it sporulates poorly in SM medium and this phenotype was partially reverted by the addition of LA. Due to these results we renamed yqhM as lipM. Notably, in B. subtilis three proteins, LipL, LipM and LipA, are essential for the endogenous protein lipoylation pathway, instead of the two-protein model of E. coli.