Adenosylmethionine synthetase from streptomyces sp., gene sequences coding the same and method for mass production of secondary metabolites including antibiotics thereof

A method for production of an antibiotic comprising the steps:

• i) producing S-adenosyl-L-methionine by transforming a Streptomyces species selected from the group consisting of Streptomyces spectabilis, Streptomyces lividans, Streptomyces avermitilis, Streptomyces cinnamonenesis, Streptomyces peucetius, Streptomyces griseus, and Streptomyces aureofaciens with an expression vector comprising a polynucleotide obtained from Streptomyces spectabilis ATCC 27741 encoding a polypeptide having the enzymatic activity of catalyzing the biosynthesis of said S-adenosyl-L-methionine, wherein said polypeptide has the amino acid sequence of SEQ ID NO:
• 2;
• and
• ii) culturing said transformed Streptomyces species producing said S-adenosyl-L-methionine in an antibiotic culture medium for the mass production of antibiotics, wherein said antibiotics are avermectin, monensin, spectinomycin, doxorubicin, streptomycin, tetracycline, chlortetracycline, actinorhodin or undecylprodigiosin.