Action of Spleen Phosphodiesterase upon Yeast Soluble Ribonucleic Acid.

A major concern in attempts to relate the structure of soluble ribonucleic acid with biological specificity is whether an entire molecule of the acid is needed for biological function. Specific monophosphatases and esonucleases offer a tool with which to approach this question. Hydrolysis of S-RNA’ with venom phosphodiesterase (1) destroys the amino acid-accepting ability of S-RNAs (2, 3), presumably through removal of the amino acid-binding site. Treatments with spleen phosphodiesterase (4) designed to remove nucleotides from the amino acid-nonbinding end* of S-RNAs have yielded conflicting results concerning the essentiality of this end of the molecule (2, 5). Further, these reports are difficult to interpret because of lack of information on the products of the hydrolyses. This paper shows that spleen phosphodiesterase does act as an esonuclease upon the amino acid-nonbinding end of yeast S-RNA and that such action results in rapid loss in the amino acid-accepting ability of yeast S-RNA.