Giant linear plasmids of β-lactam antibiotic producing Streptomyces

Abstract A survey of the total cellular DNA from five β-lactam antibiotic-producing Streptomyces spp. by pulsed field gel electrophoresis was conducted to investigate the presence of linear plasmids. Streptomyces clavuligerus NRRL 3585 contained two giant linear plasmids of 120 and 430 kb, in addition to the well-characterized 11.7 kb linear plasmid. Streptomyces griseus NRRL 3851 contained a single giant linear plasmid of 120 kb, and Streptomyces jumonjinensis NRRL 5741 contained two giant linear plasmids (220 and 280 kb), and two smaller linear plasmids. No plasmids were identified in Streptomyces cattleya NRRL 3841 or Streptomyces lipmannii NRRL 3584. Southern hybridization did not reveal any homology shared by these plasmids, and β-lactam antibiotic synthesis gene clusters were located on the chromosome.