Reconstitution of functional 50S ribosomes from in vitro transcripts of Bacillus stearothermophilus 23S rRNA

In vitro transcripts of Bacillus stearothermophilus 23S rRNA can be reconst ituted into catalytically active 50S ribosomal subunits with an efficiency only 3-4-fold lower than that of natural 23S rRNA. Thus, post-transcription al modifications in 23S rRNA are not essential for the assembly or function of the 50S subunit of the ribosome. This reconstitution system has been us ed to characterize the peptidyl transferase activity of site-directed mutat ions in 23S rRNA at positions G2252, U2506, U2584, and A2602 (Escherichia c oli numbering), demonstrating its potential for the analysis of the role pl ayed by 23S rRNA in the function of the 50S subunit of the ribosome.