A new non-protein enediyne antibiotic N1999A2: Unique enediyne chromophore similar to neocarzinostatin and DNA cleavage feature

Abstract The present NMR and X-ray structural studies demonstrated that the new antibiotic N1999A2 isolated from the broth filtrate of Streptomyces sp. AJ9493, possesses a novel 9-membered ring enediyne chromophore similar to neocarzinostatin, but is not chromoprotein. Of special interest is the fact that stable N1999A2 exists as enediyne chromophore alone as well as dynemicin A, esperamicin A 1 and calicheamicin γ 1 . The major difference between N1999A2 and neocarzinostatin chromophore is lack of the amino sugar in N1999A2. The antibiotic N1999A2 revealed more random DNA cutting profile than neocarzinostatin chromophore.