Activities of protein-deficient particles derived from 50-S ribosomal subunits by NH4Cl/ethanol treatment (original) (raw)

Protein-deficient ribosomal particles obtained by treatment of 50-S subunits from Escherichia coli ribosomes with 1 M NH4Cl and 50% ethanol contain less than 3% of proteins L7 and L12 and about 7% of proteins L10 and L11. Proteins L1, L5, L8/9 and L25 are also released during the treatment but in amounts accounting for less than 40%. The particles are able to form peptide bonds in different systems, such as 'fragment reaction', puromycin reaction and formation of dipeptides. They also bind N-acetylphenylalanyl-tRNA and phenylalanyl-tRNA non-enzymically but are unable to support any of the elongation-factor-dependent reactions tested. However, when methanol is present, they display up to 20% of the control EF-G-dependent GTP activities such as GTP hydrolysis and formation of the ternary complex EF-G-GuoPP(CH2)P-ribosome. The first activity is totally sensitive to the antibiotic thiostrepton while the formation of the ternary complex is unaffected by the drug. When measured by...