CHAPTER 12 



Evidence on the Nature of the Chemical Bonds 

 in Nucleic Acids 



D. M. BROWN AND A. R. TODD 



Page 



I. Introduction 409 



II. Chemistry of the Ribonucleic Acids 413 



1. Mononucleotides 413 



2. Esters of the Mononucleotides 415 



3. General Structure of Polyribonucleotides based on Chemical Degradation 418 



4. Evidence for Nucleoside-S'-linkages • . . , . 422 



5. Chemistry of Ribonuclease Action 423 



6. Structure of Oligonucleotides derived from Ribonucleic Acids 428 



7. Evidence for 3'(6) -linkages in Ribonucleic Acids 430 



8. Chain-branching in Ribonucleic Acids 432 



9. Nucleotide Sequence in Polyribonucleotides 436 



III. Structure of the Deoxyribonucleic Acids 439 



1. Nucleotide Sequence in Deoxyribonucleic Acids 442 



I. Introduction 



Since the emergence of reasonably clear ideas on the nature of the simple 

 nucleotides, and the recognition that the nucleic acids can be regarded as 

 polynucleotides, many attempts have been made to formulate general struc- 

 tures for them. In all such attempts the nature of the internucleotidic link- 

 age has occupied a central position and at one time or another most of the 

 possible types have been considered. The earlier developments in this field 

 have been adequately treated in a number of reviews,'"® and since they are 

 primarily of historical interest they will not be discussed here. Fortunately, 

 work in recent years has led to precise and generally accepted views on at 

 least the major portion of the internucleotidic linkages present in both 

 ribonucleic and deoxyribonucleic acids; it is therefore only necessary to 



' P. A. Levene and L. W. Bass, "The Nucleic Acids." The Chemical Catalog Co., 



New York, 1931. 

 « R. S. Tipson, Advances in Carbohydrate Chem. 1, 193 (1945). 

 'J. M. Gulland, J. Chem. Soc. 1938. 1722. 



* J. M. Gulland, J. Chem. Soc. 1944, 208. 



' J. M. Gulland, Nucleic acids, Symposia Soc. Exptl. Biol. 1, 1 (1947). 



* F. Schlenk, Advances in Enzymol. 9, 455 (1949). 



409 



