Chapter VII 



The Comparative Chemistry of Infective Virus Particles and Their 

 Functional Activity: T2 and other Bacterial Viruses 



E. A. Evans, Jr. 

 Department of Biochemistry, University of Chicago, Chicago, Illinois 



I. Introduction 459 



II. General Structure of Coliphage Particles 460 



III. The Protein Components of Coliphage Particles 461 



A. Amino Acid Content of Coliphage Proteins 461 



B. The Heterogeneity of Viral Protein 463 



IV. Nucleic Acid Components of Coliphage 468 



A. Analysis of Components of Viral Nucleic Acid 467 



B. Heterogeneity of Viral DNA 470 



V. Other Viral Specific Products 471 



Addendum 472 



References 472 



I. Introduction 



Although many bacterial viruses are known to the microbiologist, practic- 

 ally all of our quantitative chemical information concerning this group of 

 infectious agents is derived from the T series of coliphages. Among these, 

 attention has been concentrated on one or two strains and much remains to 

 be done before our chemical information, even with respect to this limited 

 group of viral agents, is adequate. The chemical study of the sperm-shaped 

 coliphage particles, formed of headpieces ranging in diameter from about 45 

 to 80 m/x and tails of varying lengths (15 X 10 m|U,-15 X 170 m^u) is compli- 

 cated by the vexatious problems of pm^ification and homogeneity, so that it 

 is difficult to evaluate the significance of differences in chemical composition 

 reported with various preparations. Since a discussion of methods of purifica- 

 tion and criteria for purity is not called for here [see Putnam (1953) for dis- 

 cussion of these topics], it suffices to say that the data selected represent, as 

 far as possible, analyses of homogeneous and purified strains. 



In general, studies of the N distribution of the T series of coliphages indi- 

 cate that about half of the N is present as nucleic acid and half as protein, 

 with small amounts of N (7 %) present as acid-soluble material. In purified 

 preparations P is present as nucleic acid, although small amounts (up to 1 %) 

 of acid-soluble P are observed (Taylor, 1946; Kozloif and Putnam, 1949; 

 Herriott and Barlow, 1952). The nucleic acid seems exclusively of the DNA 



459 



