Aranciamycin analogs generated by combinatorial biosynthesis show improved antitumor activity.

Expression of the aranciamycin biosynthetic gene cluster in Streptomyces diastatochromogenes Tü6028 resulted in production of four novel compounds, aranciamycins E, F, G, and H with different decorations in the tetracyclic backbone. Two derivatives contain a D-amicetose moiety at C7 (aranciamycins F and G), two are hydroxylated at position C1 (aranciamycins E and G), and one is hydroxylated at C13 (aranciamycin F). Analysis of the biological activities of the aranciamycins against two human tumor cell lines--MCF-7 and MATU--shows surprising impact of the hydroxyl group at position C1 on activity.

A genomic screening approach to the structure-guided identification of drug candidates from natural sources.

The potential of actinomycetes to produce natural products has been exploited for decades. Recent genomic sequence analyses have revealed a previously unrecognized biosynthetic potential and diversity. In order to rationally exploit this potential, we have developed a sequence-guided genetic screening strategy.

Cloning, purification and characterization of a functional anthracycline glycosyltransferase.

We have cloned the gene that encodes a novel glucosyl transferase (AraGT) involved in rhamnosylation of the polyketide antibiotic Aranciamycin in Streptomyces echinatus. AraGT comprises two domains characteristic of bacterial glycosyltranferases. AraGT was synthesized in E.

LanGT2 Catalyzes the First Glycosylation Step during landomycin A biosynthesis.

The glycosyltransferase LanGT2 is involved in the biosynthesis of the hexasaccharide side chain of the angucyclic antibiotic landomycin A. Its function was elucidated by targeted gene inactivation of lanGT2. The main metabolite of the obtained mutant was identified as tetrangulol (4), the progenitor of the landomycin aglycon (7).