Production of 6, 8a-Seco-6, 8a-deoxy Derivatives of Avermectins by a Mutant Strain of Streptomyces avermitilis
1995 Volume 48 Issue 1 Pages 59-66
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1995 Volume 48 Issue 1 Pages 59-66
Streptomyces avermitilis produces the anthelmintic and insecticidal secondary metabolite avermectins. Following mutagenesis of a recombinant strain, S. avermitilis K2038 (aveD X) with N-methyl-N'-nitro-N-nitrosoguanidine, a derivative strain K2057 (aveD aveE X), was isolated, which produced seven avermectin-related compounds different from the eight components of avermectins. Four among these seven compounds from mutant K2057 were found to be new metabolites. Their structures were 4'-deoleandrosyl-6, 8a-seco-6, 8a-deoxyavermectin Bla, 4'-deoleandrosyl-6, 8a-seco-6, 8a-deoxy-5-oxoavermectin Bla, 4'-deoleandrosyl-6, 8a-seco-6, 8a-deoxy-5-oxoavermectin B2a and 6, 8a-seco-6, 8a-deoxy-2, 5-didehydroavermectin B2a, all of which lack the furari ring at C-6, C-8a. The mutation affecting the formation of the furan ring (aveE) is located in the center of the gene cluster for avermectin biosynthesis.
