Direct proteomic mapping of Streptomyces Luteogriseus Strain 103 and cnn1 and insights into antibiotic biosynthesis.

Global proteome of the antibiotic-production strain 103 and the nonantibiotic-production mutant cnn1 were directly analyzed using 2D LC-MS/MS. A total of 726 and 809 proteins have been identified, respectively. Physical and chemical characterization, subcellular location and functional classification of the global protein were carried out. By searching the key enzymes of several probable antibiotic biosynthesis pathways in the identified proteins of strain 103, only polyketide synthase was found, which suggested that Maituolaimysin be synthesized through polyketide pathway. The same searching result was obtained in strain cnn1, which confirmed the conclusion drew from strain 103. Other proteins associated with the polyketide pathway of the two strains were searched according to the protein classification scheme of Streptomyces coelicolor (available at http://www.sanger.ac.uk/Projects/S_coelicolor/) and most of them were found. The activity inhibition of beta-ketoacyl ACP synthase, a key enzyme in the polyketide pathway, directly resulted in the decrease of Maituolaimysin production, which proved the conclusion obtained in the proteomic research.