Regulatory mutants of Streptomyces clavuligerus affected in free diaminopimelic acid content and antibiotic biosynthesis

Abstract

The composition of intracellular free amino acid pools was determined in Streptomyces clavuligerus mutants possessing an altered aspartokinase which is insensitive to concerted feedback inhibition by threonine and lysine. These mutants contained total free amino acid pool contents that were considerably higher than those found in the wild-type strain. Diaminopimelic acid accounted for 10 to 20% of the total free amino acid pools, depending on the individual mutant and its culture growth phase, whereas diaminopimelic acid contained in the wild-type strain accounted for only 0.5% of the total free amino acid pool.The primary metabolic pathways which provide substrates for the antibiotic-specific synthetases are principal targets for regulatory mechanisms in controlling antibiotic biosynthesis (2,9). In the case of Streptomyces clavuligerus, the cephamycin C P-lactam antibiotic producer (4), the aspartic