engleski

Analysing the switch to oxytetracycline production through phosphoproteomics in Streptomyces rimosus

Streptomycetes are multicellular bacteria that show an unusual and complex life cycle. The great majority of natural products, including clinnicaly important antibiotics (tetracyclines, streptomycins or β-lactams), immunosuppressants (rapamycin) and anti-cancer drugs (doxorubicin) are synthesized by these bacteria. The oxytetracycline (OTC) produced by S. rimosus is member of commercially significant class of antibiotics. The TCs consumption is increasing at the global market showing the need for the improvement of the TC production strains. It has been reported that protein phosphorylation has an important role in the regulation of metabolism and antibiotic production in strepomycetes. S. rimosus genom analysis predicted 33 eukaryotic-like protein kinases and 25 protein phosphatases in this species. Based on the phosphoproteome reported for S. coelicolor we predict that the effect of the OTC overproduction in S. rimosus is a consequence of alteration in posttranslational modification (PTM) of regulatory and/or OTC biosynthesis proteins. Different S. rimosus strains were tested for antibiotic production, and analysed using HPLC. Inspected strains showed great variations in OTC production. Western blot analyses showed different phosphorylation patterns for each strain while confocal microscopy revealed different morphological features and viability of tested strains. Phosphoproteomic analysis using high accuracy mass spectrometry indicated some regulatory proteins that may be employed in OTC biosynthesis. These proteins exhibited the difference in their expression at different stages of growth and in their phosphorylation status which may be a signal for triggering antibiotic biosynthesis. This is an ongoing project.

phosphorylation ; S. rimosus ; OTC production

nije evidentirano