Comparison of the distribution of “X”-like nucleosides in tRNA species of Drosophila melanogaster, with other eukaryotes and prokaryotes

Abstract

1. 1. The amount and distribution of modified nucleosides with free amino groups were analysed in Drosophila tRNA species by reaction of tRNA with the N-hydroxysuccinmide ester of napthtoxy-acetic acid followed by chromatography on benzoylated DEAE cellulose. 2. 2. The most reactive tRNAs were those of asparagine, isoleucine, threonin, valine and tyrosine. 3. 3. The presence of the reactive nucleoside(s) in individual tRNA species was analysed by chromatographing napthtoxyacetylated and BrCN treated tRNAs on RPC-5 columns. 4. 4. The distribution of the reactive nucleoside(s) appears similar to rat tRNAs but very different to E. coli where “X” 3(3-amino-3-carboxypropyl) uridine is responsible for the reactivity. 5. 5. In the two higher eukaryotes so far examined the distribution of these “X”-like nucleosides has been highly conserved while it is lacking in yeast tRNAs and very different in distribution in prokaryote tRNAs.