149] RNase hydrolysis of aminoacyl-sRNA to aminoacyl adenosine

Abstract

Publisher Summary RNase hydrolysis of aminoacyl-soluble RNA (sRNA) to aminoacyl adenosine is a means of exploring the manner of attachment of amino acids to sRNA. Digestion with pancreatic RNase of amino acid-charged sRNA rather cleanly releases the 3 ' -terminal adenosine with the amino acid linked to it. The action of RNase on aminoacyl-sRNA shows the specific cleavage adjacent to a pyrimidine nucleotide and bears out the finding that the amino acid attachment to sRNA requires the uniform 3 ' -terminal sequence of two cytidylic acids followed by an adenylic acid. Brief exposure to pH 9 liberates the amino acid from adenosine. Periodate, however, does not cause a cleavage of the aminoacyl derivative but reacts after amino acid removal. This characterizes the linkage as an ester bond to one of the adjacent 2 ' or 3 ' OH of the ribose in adenosine. The point of attachment is shown to be rather complicated because of the ease of transacylation between the two positions. The isolation of aminoacyl adenosine from a fresh organ and rat liver is described in the chapter as an example of the general procedure.