Overexpression of yeast S-adenosylmethionine synthetase metK in Streptomyces actuosus leads to increased production of nosiheptide.

S-Adenosylmethionine (SAM) is synthesized via the metabolic reaction involving adenosine triphosphate and L-methionine that is catalyzed by the enzyme S-adenosyl-L-methionine synthetase (SAM-s) and encoded by the gene metK. In the present study, metK with the absence of introns from Saccharomyces cerevisiae was introduced into Streptomyces actuosus, a nosiheptide (Nsh) producer. Intracellular SAM levels were determined by high-pressure liquid chromatography. Through optimizing the nutrient content of the medium, it was shown that increased SAM production induced by the overexpression of SAM-s leads to an increase in the intracellular cysteine pool and overproduction of Nsh in S. actuosus. This investigation shows that increased SAM promotes the elevated production of the non-ribosomal thiopeptide Nsh in Streptomyces sp.