INVESTIGADORES
CASATI Paula
artículos
Título:
Impact of Malic Enzymes on Antibiotic and Triacylglycerol Production in Streptomyces coelicolor
Autor/es:
EDUARDO JOSE RODRIGUEZ; LAURA NAVONE; PAULA CASATI; HUGO GRAMAJO
Revista:
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
Editorial:
AMER SOC MICROBIOLOGY
Referencias:
Lugar: Washington; Año: 2012 vol. 78 p. 4571 - 4579
ISSN:
0099-2240
Resumen:
In this paper, we have characterized two malic enzymes (ME), SCO2951 and SCO5261, from Streptomyces coelicolor
and analyzed their role in antibiotic and triacylglycerol (TAG)
production. Biochemical studies have demonstrated that Sco2951 and
Sco5261 genes encode NAD+- and NADP+-dependent
malic enzymes, respectively. Single or double mutants in the ME-encoding
genes show no effect on growth rate compared to the parental M145
strain. However, the single Sco2951 and the double Sco2951 Sco5261
mutants display a strong reduction in the production of the polyketide
antibiotic actinorhodin; additionally, the Sco2951 Sco5261 mutant shows a
decrease in stored TAGs during exponential growth. The lower production
of actinorhodin in the double mutant occurs as a consequence of a
decrease in the expression of actII-ORF4, the transcriptional
activator of the actinorhodin gene cluster. On the other hand, the
reduced TAG accumulation is not due to reduced transcript levels of
fatty acid biosynthetic genes nor to changes in the amount of the
precursor acetyl coenzyme A (acetyl-CoA). This mutant accumulates
intermediates of the tricarboxylic acid (TCA) cycle that could alter the
regulation of the actinorhodin biosynthetic pathway, suggesting that
MEs are important anaplerotic enzymes that redirect C4 intermediates
from the TCA cycle to maintain secondary metabolism and TAG production
in Streptomyces.