On the similarity between the tRNAs of organelles and prokaryotes

Fluorescence studies with organelle transfer RNAs separated from their cytoplasmic counterparts revealed that phenylalanine tRNA from Euglena chloroplasts or Neurospora mitochondria does not contain a fluorescent "base Y." In contrast, cytoplasmic phenylalanine tRNA from Euglena and cytoplasmic tRNA from Neurospora were found to contain fluorescent bases. The fluorescence-emission spectra of Neurospora cytoplasmic tRNAs and those of the related ascomycete Saccharomyces cerevisiue were observed to be quite different. The results support the generalization that eukaryotic tRNAs contain a fluorescent base, but indicate that their respective organelle tRNAs do not. They also indicate a striking parallelism between organelle and prokaryotic tRNAs.