Part I. Properties of Helical Polycytidylic Acid. Part II. Interactions of Purine with Proteins and Amino Acids. Part III. Binding of Basic Proteins to DNA

This thesis is divided into three sections. The first part deals with the secondary structure of poly C in acid solution, as revealed by several of its physical-chemical properties in solution. The interpretation of the data was based on previous knowledge of the general properties of polynucleotides in solution and on the properties of poly C monomer. The second part of the thesis deals with the interaction of purine with the proteins. Conformation changes in the proteins are easily measurable in terms of changes in optical rotation even at the visible wavelength regions. Full use was made of this fact to study the nature of interaction of purine with the proteins. The most significant aspect of the studies is not the theoretical speculation on the mechanism of the interaction, but rather the possible practical applications of the findings. This is briefly considered in the discussion. The mechanism of urea. interaction with the proteins cannot be regarded as solved in spite of the voluminous literature on the subject. Similarly, the mechanism of purine interaction with proteins cannot be regarded as solved. The speculations presented at length on the mechanism of the interactions of purine or urea with the proteins, therefore, merely represent a simplified deduction from available data -- a deduction intended to stimulate more experiments and perhaps a modified interpretation of the nature of the interactions. The third part of the thesis presents initial findings on a very complex problem -- the relationship of polyvalent polymer-polymer interactions to some of their other physical-chemical and biochemical properties. The conclusions drawn from the data are not new or peculiar to current thinking about the nature of interaction of the histones or protamines to DNA. However, certain satisfactions are derived from the fact that it has been possible to carry out reliable physical-chemical measurements on the nucleohistone and nucleoprotamine systems by means of simple standard techniques. Such data are rare in the nucleohistone or nucleoprotamine literature. No doubt, the confirmation of more complex findings on these very important systems will often require these simple physical-chemical data.