Coding Properties of Methyl-Deficient Phenylalanine Transfer RNA

Abstract

Studies in several laboratories have shown that RNA from plant, animal, and bacterial sources contain small amounts of methylated bases. The highest proportion of these methylated bases occurs in tRNA. Transfer RNA (tRNA) species isolated from various sources differ in the number and type of methylated bases they contain. The minor nucleotides of each amino acid-specific tRNA chain occupy definite positions along the RNA chain (Holley et al., 1963, Cantoni et al., 1963; Ingram and Sjoquist, 1963; Bank et al., 1964; Dütting and Zachau, 1964); yeast alanine tRNA contains one 1-methyl guanylic acid but no methylated cytidylic acids (Holley et al., 1965), serine tRNA contains 5-methyl cytidylic acid but no 1-methyl guanylic acid (Zachau et al., 1966). On the other hand, ribothymidilic acid appears in nearly all polynucleotide chains. It is found in the unique pentanucleotide sequence GpTpΨpCpG which so far has been detected in...