THE NUCLEOTIDE-SEQUENCE OF PHENYLALANINE TRANSFER-RNA AND 5S-RNA FROM RHODOSPIRILLUM-RUBRUM

The complete nucleotide sequence of tRNAPhe and 5S RNA from the photosynthetic bacterium R. rubrum was elucidated. A combination of in vitro and in vivo labeling techniques was used. The tRNAPhe sequence is 76 nucleotides long, 7 of which are modified. The primary structure is typically prokaryotic and is most similar to the tRNAPhe of Escherichia coli and Anacystis nidulans (14 differences of 76 positions.) The 5S rRNA sequence is 120 nucleotides long and again typical of other prokaryotic 5S RNAs. The invariable GAAC sequence is found starting at position 45. When aligned with other prokaryotic 5S RNA sequences, a surprising amount of nucleotide substitution is noted in the prokaryotic loop region of the R. rubrum 5S RNA. Nucleotide complementarity is maintained reinforcing the hypothesis that this loop is an important aspect of prokaryotic 5S RNA secondary structure. The 5S and tRNAPhe are the first complete RNA sequences available from the photosynthetic bacteria.