Chemochromatography: its use for the separation of nikkomycins X and Z

A practical and scalable manufacturing process for an anti-fungal agent, Nikkomycin Z

A scalable and reliable manufacturing process for Nikkomycin Z HCl on a 170 g scale has been developed and optimized. The process is characterized by a 2.3 g/L fermentation yield, 79% purification yield, and >98% relative purity of the final product. This method is suitable for further scale up and cGMP production. The Streptomyces tendae ΔNikQ strain developed during the course of this study is superior to any previously reported strain in terms of higher yield and purity of Nikkomycin Z.

A search for pyrophosphate mimics for the development of substrates and inhibitors of glycosyltransferases

The design and synthesis of several beta-1,4-galactosyltransferase inhibitors are reported. Mimics of the pyrophosphate-Mn2+ complex were the focus of the design. Malonic, tartaric, and monosaccharide moieties were used as replacements of the pyrophosphate moiety, and galactose or azasugars with potent galactosidase inhibitory activity were used as the 'donor' component. Compound 6, in which glucose was used as the pyrophosphate-Mn2+ complex mimic and galactose as the 'donor' component, showed the best inhibitory activity towards the transferase with a Ki of 119.6 microM.

Conformational studies of nikkomycin X in aqueous solution

Nikkomycin X is a peptidyl-nucleoside antibiotic that inhibits chitin synthesis in fungi. Information on its conformation in aqueous solution was obtained from pH titration studies in which the nmr shifts of exchangeable and nonexchangeable protons were monitored. These studies and nuclear Overhauser effects support an unfolded or conformationally flexible structure for the antibiotic, and the syn and anti conformations of the nucleoside moiety were found to coexist. The conformation of the ribose ring was determined using a two-state model; a slight shift from type N to type S conformers occurred as the pH was raised from 1 to 6.

High-performance liquid chromatography separation of nikkomycins X and Z

A reversed-phase, C-18 HPLC method for separation, with baseline resolution, of the chitin synthase inhibitors nikkomycin X and Z is described. This permits, for the first time, satisfactory identification of nikkomycin X and Z contained in a mixture. The use of 30 mM ammonium formate (pH 4.7) containing the ion-pair agent heptanesulfonic acid (1 mM) was critical for the successful separation of these fungicides.

Mutation affecting peptide bond formation in nikkomycin biosynthesis

Nikkomycin, a nucleoside-peptide analog of UDP-N-acetylglucosamine, is a potent chitin synthase inhibitor produced by the bacterium Streptomyces tendae. The HPLC profile of fermentation products in culture broths of a non-producing mutant, Nik 15, was compared with nikkomycin standards. Nikkomycin C and D, the glycone and aglycone moieties, respectively, of nikkomycin Z accumulated. This indicates the mutation affects the capacity to form a peptide bond between nikkomycin C and D, which is here proposed to be the terminal step in the synthesis of the biologically active nikkomycin Z. This is also the first documented case of a mutation affecting a specific step in nikkomycin biosynthesis.