THE ARRANGEMENT OF PURINE AND PYRIMIDINE NUCLEOTIDES IN TOBACCO MOSAIC VIRUS NUCLEIC ACID

Abstract

Information pertaining to th.e mode of arrangement of some of the purine and pyrimidine nucleotides in tobacco mosaic virus nucleic acid (TMV-NA) was obtained using nucleases such as pancreatic ribonuclease and micrococcal phos-phodiesterase. These results show that in addition to both the purine nucleotides and pyrimidine nucleotides occurring in clusters of 2 or more, they also exist singly alternating with each other. The latter type of arrangement appears not to be so frequent as the former. There is a definite regularity in the arrangement of both the purine and pyrimidine nucleotides in TMV-NA, suggesting that the arrangement is not of a random type. Products obtained by digestion of nucleic acids of TMV, HR and M strains, with pancreatic ribonuclease, revealed significant differences in the mode of arrangement of purine and pyrimidine nucleotides in each of these molecules. This information provides evidence that the genetic specificity of a nucleic acid resides in the arrangement of its components, namely the purine and pyrimidine nucleotides.