The binding site of ribosomal protein L1 from Escherichia coli on the 23-S ribosomal RNA from Bacillus stearothermophilus. A possible base-pairing scheme differing from that proposed for Escherichia coli.

The region of Bacillus stearothermophilus strain NCA 1503 23-S ribosomal RNA protected from T1 ribonuclease digestion by the 50-S ribosomal subunit protein L1 from Escherichia coli has been established. The sequence of 115 nucleotides is compared to the analogous region in E. coli. The similar behaviour of the RNA towards the recognition of protein L1 may be explained in terms of secondary base-pairing, even though there exists almost 40% difference between the primary nucleotide sequences.