Nucleotide sequence of wheat chloroplastid 4.5 S ribonucleic acid: sequence homologies in 4.5 S RNA species

The nucleotide sequence of wheat (Triticum aestivum L.) chloroplastid ribosome-associated 4.5 S RNA is U-A-A-G-G-U-G-A-G-C-G-G-C-G-A-G-A-C-G-A-G-C-C-G-U-U-U-A-A-A-U-A-G-G-U-G-U-C-A-A -G-U-G-G-A-A-G-U-G-C-A-G-U-G-A-U-G-U-A-U-G-C-A-G-C-U-G-A-G-G-C-A-U-C-C-U-A-A-C- G-A-A-C-G-A-A-C-G-A-U-U-U-G-A-A-COH. The sequence is highly conserved among chloroplastid 4.5 S RNAs but not related to either the 5 S or 5.8 S rRNA species. When compared with 4.5 S RNAs from other origins, the results indicate that this molecule bears little sequence homology to the mammalian nuclear 4.5 S RNA but suggest that chloroplastid 4.5 S RNA may be related to the bacerial 4.5 S species. An estimate for the secondary structure of the wheat 4.5 S molecule was deduced from products of limited pancreatic and T1 ribonuclease digestion, and similarities with the Escherichia coli 4.5 S RNA are discussed.