54 



The Structure of Protoplasvi 





I I B 



->icQlQ5Ak- 



■^**^%M''^*'^if^- 



■^^^^-"^•^^M-^- 



i_. 



ca4.5A 



'v^^lltiM -***^1iti»^- •'^^"^liti^ 



A 



c 



Fig. 5. Model photographs showing three faces of a packet of parallel pro- 

 tein chains. A. Three rows of seven chains each showing ends of the chains. 

 Note flat shape of individual units when viewed in this direction; width ap- 

 proximately 10.5A, thickness about 4.5A. B. Top view of same packet. C. Side 

 view. 



is a strong probability that water molecules, by means of hydrogen 

 bridges, may form a seam between adjacent backbones (54). The 

 spacing may then become about 7 A instead of 4.5 A as when dry. 

 The hydrophilic end groups may furnish loci for hydrogen bridges 

 between the layers within a particle and also between particles. 

 Here the distribution of the oxygen- and nitrogen-bearing residues 

 is effective in furnishing few or many bridges according to the 



