Identification of four genes from the granaticin biosynthetic gene cluster of Streptomyces violaceoruber Tü22 involved in the biosynthesis of L-rhodinose.

Four genes, ORF 22 approximately 25, from the granaticin biosynthetic gene cluster of Streptomyces violaceoruber Tü22 were analyzed for their involvement in the biosynthesis of the two deoxysugar moieties of the granaticins. Each gene was individually inactivated on a cosmid carrying the entire gra gene cluster and the mutant cosmids were transformed into S. coelicolor CH999.

The granaticin biosynthetic gene cluster of Streptomyces violaceoruber Tü22: sequence analysis and expression in a heterologous host.

Background: The granaticins are members of the benzoisochromanequinone class of aromatic polyketides, the best known member of which is actinorhodin made by Streptomyces coelicolor A3(2). Genetic analysis of this class of compounds has played a major role in the development of hypotheses about the way in which aromatic polyketide synthases (PKSs) control product structure. Although the granaticin nascent polyketide is identical to that of actinorhodin, post-PKS steps involve different pyran-ring stereochemistry and glycosylation.