MACROMOLECULAR AGGREGATES IN CALCIFICATION 



57 



r. 



screw repeat in the case of polyglycine, for example, is 9.3 A, and the rise per 

 residue (each of which is represented here by a black dot) is 3.1 A. (E) X-ray 

 difFraction pattern of oriented collagen fibers. 



is apparent. The concept that one or more components of the 

 organic matrix of bone, cartilage, and tooth catalyzed the formation 

 of apatite crystals was first proposed by Nemnan and Neuman 

 (1953). 



From solutions of collagen extracted from a wide variety of con- 



