Ammonium ions suppress the amino acid metabolism involved in the biosynthesis of protylonolide in a mutant of Streptomyces fradiae.

THE JOURNAL OF ANTIBIOTICS MECHANISM OF NITROGEN REGULATION OF PROTYLONOLIDE BIOSYNTHESIS IN STREPTOMYCES FRADIAEt

A resting cell system was used to study the sites of inhibition by NH4+ of protylonolide biosynthesis by a blocked mutant, strain 261, of Streptomyces fradiae. With 14C-labeled succinate or valine as an exogenous substrate, labeled protylonolide formation by high-NH4+ grown mycelia of strain 261 was lower than by low-NH4+ grown mycelia. When 14C-labeled palmitate or acetate + labeled propionate...

Production of mycarosyl protylonolide by a mycaminose idiotroph from the tylosin-producing strain Streptomyces fradiae KA-427.

Novel fermentation products from Streptomyces fradiae: X-ray crystal structure of 5-O-mycarosyltylactone and proof of the absolute configuration of tylosin.

5-O-Mycarosyltylactone has been isolated as a predominant factor from fermentation broths of a Streptomyces fradiae mutant. The relative configurations of mycarose and tylactone (protylonolide) have been determined by X-ray crystal structure analysis. Hydrolysis of 5-O-mycarosyltylactone yielded (-)-tylactone and L-(-)-mycarose. Taken together, these two experiments establish the absolute confi...

An Evolutionary Relationship Between Stearoyl-CoA Desaturase (SCD) Protein Sequences Involved in Fatty Acid Metabolism

Background: Stearoyl-CoA desaturase (SCD) is a key enzyme that converts saturated fatty acids (SFAs) to monounsaturated fatty acids (MUFAs) in fat biosynthesis. Despite being crucial for interpreting SCDs’ roles across species, the evolutionary relationship of SCD proteins across species has yet to be elucidated. This study aims to present this evolutionary relationship based on amino aci...

Elucidation of structure of novel macrolide antibiotics produced by mutant strains of Streptomyces fradiae.

Tylosin is a 16-membered macrolide antibiotic which is produced commercially by strains of Streptomyces fradiae'•1' and is composed of a substituted lactone (tylonolide), an amino sugar (mycaminose) and two neutral sugars (mycinose, mycarose)'). Recently, a series of mutants of S. fi•adiae which are blocked in specific steps in the biosynthesis of tylosin has been described". From an analysis o...