Streptomyces echinatus

Peptidelike macrocyclic antibiotics of dimeric and trimeric form are often found, an example being echinomycin A (quinomycin A) produced by Streptomyces echinatus from the soil of Cuanza (Angola). The complete structure of a large peptide macrocycle bearing two 2-quinoxalinyl substituents has been elucidated by Prelog and co-workers.183... 

C15H21N7O5 379.375 From Streptomyces griseolus and Streptomyces echinatus. Antifungal agent. [a]g -15.8 (H2O). 

Streptonigrin was first isolated in 1959 in the United States from a culture of Streptomyces flocculus (/). The same compound was independently isolated in the Soviet Union a few years later from a strain of Actinomyces albus var. bruneomycini (2) and in France from S. rufochromogenes and S. echinatus (3), the antibiotic being named bruneo-mycin and rufochromomycin, respectively. The antibiotic forms dark brown crystals which are slightly soluble in water, lower alcohols, ethyl acetate or chloroform and more soluble in dioxane, pyridine, DMF or THF. Streptonigrin has UV absorption maxima in methanol at 248 nm (e 38,400) and 375—380 nm (e 17,400). It is a monobasic acid with pKa 6.2—6.4 in 1 1 dioxane water. 

---