Transcriptional Studies on a Streptomyces clavuligerus oppA2 Deletion Mutant: N -Acetylglycyl-Clavaminic Acid Is an Intermediate of Clavulanic Acid Biosynthesis

Abstract

The oppa2 gene encodes an oligopeptide permease essential for the production of clavulanic acid. A transcriptomic analysis of S. clavuligerus Δ oppA2 :: aac in comparison to the parental strain S. clavuligerus ATCC 27064 is reported. The lack of OppA2 results in different expression of 233 genes, including genes for proteases and genes for transport systems. The expression of the clavulanic acid genes in the oppA2 mutant is not significantly affected, but the genes for holomycin biosynthesis are strongly upregulated, in agreement with the higher holomycin production by this strain. The oppA2 -mutant is known to release N -acetylglycyl-clavaminic acid to the broth. Cosynthesis assays using non-clavulanic acid-producing mutants showed that the addition of pure N -acetylglycyl-clavaminic acid to mutants in which clavulanic acid formation was blocked resulted in the recovery of clavulanic acid production, but only in mutants blocked in the early steps of the pathway. This suggests that N -acetylglycyl-clavaminic acid is a previously unknown late intermediate of the clavulanic acid pathway.