S-Adenosylmethionine (SAM) and antibiotic biosynthesis: effect of external addition of SAM and of overexpression of SAM biosynthesis genes on novobiocin production in Streptomyces.
Arch Microbiol
; 192(4): 289-97, 2010 Apr.
Article
em En
| MEDLINE
| ID: mdl-20177662
ABSTRACT
The production of antibiotics in different Streptomyces strains has been reported to be stimulated by the external addition of S-adenosylmethionine (SAM) and by overexpression of the SAM synthetase gene metK. We investigated the influence of SAM addition, and of the expression of SAM biosynthetic genes, on the production of the aminocoumarin antibiotic novobiocin in the heterologous producer strain Streptomyces coelicolor M512 (nov-BG1). External addition of SAM did not influence novobiocin accumulation. However, overexpression of a SAM synthase gene stimulated novobiocin formation, concomitant with an increase of the intracellular SAM concentration. Streptomyces genomes contain orthologs of all genes required for the SAM cycle known from mammals. In contrast, most other bacteria use a different cycle for SAM regeneration. Three secondary metabolic gene clusters, coding for the biosynthesis of structurally very different antibiotics in different Streptomyces strains, were found to contain an operon comprising all five putative genes of the SAM cycle. We cloned one of these operons into an expression plasmid, under control of a strong constitutive promoter. However, transformation of the heterologous novobiocin producer strain with this plasmid did not stimulate novobiocin production, but rather showed a detrimental effect on cell viability in the stationary phase and strongly reduced novobiocin accumulation.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
S-Adenosilmetionina
/
Novobiocina
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Streptomyces coelicolor
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Antibacterianos
Idioma:
En
Revista:
Arch Microbiol
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Alemanha