THE TERMINAL GROUPS OF RIBONUCLEATE CHAINS IN EACH OF THE 16S AND 23S COMPONENTS OF ESCHERICHIA COLI RIBOSOMAL RNA

Abstract

Ribosomal ribonucleates from Escherichia coli have been resolved into 16S and 28S components by sucrose density-gradient centrifugation, and the chain termini in each of the 16S and 23S RNA components have been analyzed by hydrolysis with alkali. The principal 5′-linked end group of 16S RNA was found to be adenosine, and the principal 5′-linked end group of 23S RNA was found to be uridine. The principal 3′-linked end group of 16S RNA was also found to be adenosine, whereas the principal 3′-linked end group of 23S RNA was found to be guanosine. Quantitative estimates of chain length based on analyses for 5′-iinked terminals indicate that the mean chain length for 16S RNA is about 1.3 × 103nucleotide residues and the mean chain length for 23S RNA is about 2.1 × 103nucleotide residues.