Streptomyces collinus

Naphthomycins, Naphthoquinomycins, Actamycin, and Diastovaricins. I he naphthomycins are a group of closely related antibiotics differing in the substituent at C-2 and C-30, and in the geometry about the C-4 and C-6 double bonds. The naphthoquinomycins, diastovaricins. and actamycin are all closely related to the naphthomydns. Naphthomycin A is isolated from a fermentation beer of Streptomyces collinus (Tii 105). 

Tlie side chain of tlie antifungal antibiotic ansatrienin A from Streptomyces collinus contains a cylohexanecai boxyhc acid (CHC)-derived moiety. Tliis moiety is also observed in... 

Naphthomycin A (56) was isolated as a yellow pigment from the cultured broth of Strain Tii 105 of Streptomyces collinus. 

Accordingly, it was shown that mycotrienins I (95) and II (96) possessed the same structures as those of the ansamycin antibiotics designated as ansatrienins A and B isolated from the fermentation broth of Streptomyces collinus [161, 162], except for the configuration of the alanine moiety. Thus, the alanine moiety of the ansatrienins was reported to be L, and was later revised to be d (the same configuration as those of mycotrienins). Ansatrienins A2 (100) and A3 (101) were isolated as minor congeners of ansatrienins A (95) and B (96) from the same fermentation broth [163]. 

The biosynthetic origin of the cyclohexanecarboxylic acid moiety of the mycotrienins I (95) and II (96) was also considered to be shikimic acid (119) [184,204]. Cell-free extracts of Streptomyces collinus were tested with various cyclohexene- and cyclohexadiene-carboxylic acids in order to determine the latter stages of the conversion of 119 to cyclohexanecarboxylic acid. It was demonstrated that the final three steps of this process involve reduction of the a,P-double bond of 1,2(6)-cyclohexadienylcarbonyl CoA, an isomerization of the double bond of the resulting 2-cyclohexenylcarbonyl CoA to afford 1-cyclohexenylcarbonyl CoA, and a subsequent reduction of the newly formed a,P-double bond. Both of the reduction steps were shown to require NADPH as a cofactor [212]. 

---