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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 proteins 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 15 918 Da and 15 690 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. [ABSTRACT FROM AUTHOR]

The complete amino acid sequence of ribosomal protein L2 from the moderate thermophile Bacillus stearothermophilus has been determined. This has been achieved by the sequence analysis of peptides derived by enzymatic digestion with Staphylococcus aureus protease, trypsin and chymotrypsin, as well as by chemical cleavage with o-iodosobenzoic acid. The protein contains 275 amino acid residues and has a calculated molecular mass of 30201 Da. Comparison of this sequence with sequences of the corresponding proteins from Escherichia coli and from spinach and tobacco chloroplasts reveals that 60% of the residues of protein L2 from B. stearothermophilus are identical to those of the protein from E. coli and 45% are identical to those found in the two chloroplast proteins. There are extended regions of totally conserved sequence at positions 54-58 (GGGHK), 81-86 (EYDPNR), and 224-230 (MNPVDHP) in all four proteins. [ABSTRACT FROM AUTHOR]