Lysyl-tRNA synthesis

Studying the lysyl-tRNA synthesis it was shown that... 

Another important technique was based on the observation that synthetic trinucleotides induced the binding to ribosomes of tRNA molecules that were "charged" with their specific amino acids 38/39 For example, the trinucleotides UpUpU and ApApA stimulated the binding to ribosomes of 14C-labeled phenylalanyl-tRNA and lysyl-tRNA, respectively. The corresponding dinucleotides had no effect, an observation that not only verified the two codons but also provided direct evidence for the triplet nature of the genetic code. Another powerful approach was the use of artificial RNA polymers, synthesized by combined chemical and enzymatic approaches.40 For example, the polynucleotide CUCUCUCUCU led to the synthesis by ribosomes of a regular alternating polypeptide of leucine and serine. 

This synthesis of Ap4A (our abbreviation for the compound in reaction (III)) during the course of the usual activation reaction was not restricted to the lysyl synthetase activating en me system but we have found the latter to be a convenient one with which to work, since the enzyme is easily purified, relatively stable over a long period of storage in the frozen state, and inasmuch as its activation does not require the presence of tRNA, although its rate is accelerated by the latter. >... 

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