ABSTRACT
Classic genetic crosses, using nonproducing mutants, showed that genes that code for the biosynthesis of actinorhodin, undecylprodigiosin, and oxytetracycline are clustered on a chromosome of different Streptomyces species. In this chapter, the authors discuss the antibiotic biosynthetic genes cloned by using Streptomyces host-vector systems. Since the antibiotic biosynthetic genes are almost inevitably found in clusters, the antibiotic-resistance genes are useful as probes to isolate the genes coding for specific enzymes involved in antibiotic biosynthesis. The brpA can activate the transcription of the bialaphos-resistance gene as well as at least six other bap structural genes. G Erythromycin is a clinically important macrolide antibiotic produced by S erythreus. The antibiotic, a functional analogue of the aminoacyl tRNA, inhibits protein synthesis by substituting for the incoming coded aminoacyl tRNA, and serving as acceptor for the nascent peptide chain of the ribosome-bound peptidyl tRNA.
