The nucleotide sequence of spinach cytoplasmic 5 S ribosomal RNA

The nucleotide sequence of the cytoplasmic 5 S ribosomal RNA from Spinacia oleracea has been determined. A secondary structural model possessing four base-paired regions can be constructed from the primary structure. This RNA shows 90 to 93% nucleotide sequence homology with other higher plant cytoplasmic 5 S RNAs and 73% homology with that of the lower eukaryote Chlorella. The spinach 5 S RNA has the nucleotide sequence identical with that of Chlorella in two important single-stranded regions, the sequence C10 AUACC and the dodecanucleotide sequence at positions 33 to 44. A nucleotide sequence similar or identical with C10 AUACC is found in most other eukaryotic 5 S RNAs, including the 5 S RNA from human KB cells. In addition, a single-stranded loop of 12 residues corresponding to positions 33 to 44 in the spinach 5 S RNA sequence may be a general feature of eukaryotic cytoplasmic 5 S RNAs, while prokaryotic 5 S RNAs have a 13-member loop for the corresponding residues. Several other important homologies in primary and secondary structure have also been observed in comparing spinach 5 S RNA to other 5 S RNAs.