Identification of the post-polyketide synthase modification enzymes for fostriecin biosynthesis in Streptomyces pulveraceus.

Fostriecin (FST, 1) is a natural product with promising antitumor activity produced by Streptomyces pulveraceus. Its antitumor activity is associated with the selective inhibition of protein phosphatase activities. The biosynthetic gene cluster for FST has recently been cloned and sequenced.