Ribosomal proteins of Streptomyces granaticolor

Abstract

A method for large-scale isolation of streptomycete ribosomal subunits involving centrifugation in hyperbolic sucrose density gradients in a zonal rotor was developed. Ribosomal proteins were extracted from 30 S and 50 S subunits of Escherichia coli A19 and primary mycelium of Streptomyces granaticolor. Their two-dimensional electropherograms differed considerably. Purified 30 S and 50 S subunits from S. granaticolor mycelium contained 21 and 36 ribosomal proteins, respectively. Only 8 proteins in the mycelial ribosomes possessed identical electrophoretic mobilities as corresponding E. coli ribosomal proteins, viz., S4, S12, S16, L1, L2, L14, L16 and L19. Despite the differences in physico-chemical properties, functional correspondence is likely to exist between certain ribosomal proteins from the two bacteria. The range of molecular weights of vegetative S. granaticolor ribosomal proteins was similar to that in other prokaryotes. Ribosomal proteins were further isolated from 70 S ribosomes of S. granaticolor dormant spores. The spore ribosomal proteins differed markedly from those of the primary mycelium and their total number was lower. The ribosomal protein alterations are presumed to take part in the regulation of the streptomycete cell differentiation.