THE CHEMICAL NATURE OF THE RNA-AMINO ACID COMPOUND FORMED BY AMINO ACID-ACTIVATING ENZYMES

Abstract

Purified leucine-, valine-, and methionine-activating enzymes from Escherichia coli catalyze the transfer of these amino acids to a specific fraction of ribonucleic acid (RNA) according to the following general equation adenosine triphosphate + amino acid + RNA [image] amino acid-RNA + pyrophosphate + adenine monophosphate. The acceptor activity of HNA is lost after destruction or removal of the terminal nucleotide having the free 3[image]hydroxyl group by periodate or the action of snake venom phosphodiesterase. If an amino acid is linked to RNA prior to treatment with periodate, the acceptor site specific for the bound amino acid is protected against inactivation while all others are destroyed. Treatment of leukocyl-RNA with pancreatic ribonuclease results in the liberation of leucyl 2[image]- or 3[image]-adenosine. All of these observations are consistent with the hypothesis that each amino acid is linked to a specific polynucleotide chain through linkage of the amino acid to the 2[image]- or 3[image]-hydroxyl group of the terminal nucleotide of the chain.