Location of the binding region for 23S ribosomal RNA on ribosomal protein L2 from Bacillus stearothermophilus.

Tryptic and chymotryptic digestions of a complex between ribosomal protein L2 and the 23S RNA of Bacillus stearothermophilus produced two protected fragments (designated TF and CF). These protein fragments remained tightly bound to the RNA and were able to rebind specifically to 23S RNA. Amino acid sequence analysis of the isolated fragments revealed that both fragments TF and CF originated from the central half of the protein L2 (positions 60-206 and 58-201) with molecular masses of 15918 Da and 15690 Da respectively. From these results it is concluded that the protected central half is the primary RNA-binding region of the protein L2. A combination of these and other results suggests that the N and/or C-terminal (but not the central) regions may be involved in the peptidyltransferase activity of the 50S subunit.