Antidiabetic profiling of veramycins, polyketides accessible by biosynthesis, chemical synthesis and precursor-directed modification

Cyclosporins--new analogues by precursor directed biosynthesis.

Cyclosporin A (ciclosporin), a potent and clinically important immunosuppressive drug (Sandimmun), represents the main component of a group of over 25 closely related, cyclic undecapeptides produced by the fungus Tolypocladium inflatum. By feeding experiments using DL-alpha-allylglycine as precursor, specific incorporation in position 2 was attained leading to [Allylgly2]cyclosporin A. Exogenou...

Precursor directed biosynthesis of aureobasidins.

The antifungal antibiotic aureobasidin A (AbA) is a cyclic depsipeptide composed of eight amino acids and a hydroxy acid. New Ab analogs were produced by feeding various amino acids to Aureobasidium pullulans R 106 c-712 in a chemically-defined medium containing glucose and ammonium sulfate. The constituent amino acids of AbA at positions 3 (L-phenylalanine), 4 (N-methyl-L-phenylalanine), 5 (L-...

Production of novel rapamycin analogs by precursor-directed biosynthesis.

The natural product rapamycin, produced during fermentation by Streptomyces hygroscopicus, is known for its potent antifungal, immunosuppressive, and anticancer activities. During rapamycin biosynthesis, the amino acid l-pipecolate is incorporated into the rapamycin molecule. We investigated the use of precursor-directed biosynthesis to create new rapamycin analogs by substitution of unusual l-...

Novel soraphens from precursor directed biosynthesis.

Six novel halogenated soraphen analogues have been isolated from the wild-type producing organism using precursor directed biosyntheses; the best 'delivery vehicle' for the novel starter acids was cinnamate but ortho substituents were not tolerated by the soraphen PKS.

[Engineered biosynthesis of plant polyketides].