[Cloning and sequencing the isopenicillin N synthetase(IPNS) gene from Streptomyces cattleya]

Great homology existed between IPNS genes from surphur-containing beta-lactam antibiotics producers including procaryotes and eucaryotes. A DNA homologous band was confirmed in S. cattleya by Southern blot analysis using IPNS gene from S. lipmanii as a probe. A recombinant plasmid containing the cyclase gene involved in thienamycin biosynthesis and IPNS gene was obtained by complementary cloning with mutant from S. cattleya. DNA sequencing revealed that the IPNS gene of S. cattleya consists of 963 bp encoding a protein of 321 amino acids with ATG as start codon, TGA as stop codon. Pairwise comparison of the predicted amino acid sequences showed 56% and 64% similarity with IPNSs of S. clavuligerus and S. lipmanii, respectively.