Enhanced expression of S-adenosylmethionine synthetase causes overproduction of actinorhodin in Streptomyces coelicolor A3(2).

ABSTRACT: We found that a 46-kDa protein is highly expressed in an actinorhodin-overproducing Streptomyces coelicolor A3(2) mutant (KO-179), which exhibited a low-level resistance to streptomycin. The protein was identified as S-adenosylmethionine (SAM) synthetase, which is a product of the metK gene. Enzyme assay revealed that SAM synthetase activity in strain KO-179 was 5- to 10-fold higher than in wild-type cells. The elevation of SAM synthetase activity was found to be associated with an increase in the level of intracellular SAM. RNase protection assay revealed that the metK gene was transcribed from two distinct promoters (p1 and p2) and that enhanced expression of the MetK protein in the mutant strain KO-179 was attributed to elevated transcription from metKp2. Strikingly, the introduction of

SUBMITTER: Okamoto S 

PROVIDER: S-EPMC145329 | biostudies-literature | 2003 Jan

REPOSITORIES: biostudies-literature