30 



MACROMOLECULAR COMPLEXES 



NATIVE 



Qj d Qi 02 d Qi Qg d a I Qj 



S L S 



Fig. 11. Diagrammatic interpretation of the packing arrangements of the 

 TC macromolecules in the dimorphic ordered forms shown in Figs. 9 and 10. 

 To minimize complexity, only three of the twelve or so bands actually observable 

 in the native-type structure are depicted. Note that in both the SLS-type and 

 native-type structures, all staining loci are in accurate transverse alignment, 

 i.e., in register. However, in the SLS-type, only like features are in register, i.e., 

 "homo-register," while in the native-type structure, all bands arise by align- 

 ment of the four corresponding "equivalent loci" of the TC macromolecule, i.e., 

 "hetero-register." In the SLS band terminology proposed by Hodge and Schmitt 

 (1960), the superscripts refer to the subscripts in the generally accepted band 

 nomenclature for the native-type fibril, the subscripts to the four corresponding 

 "equivalent loci" in the TC macromolecule. Thus, for example, the Oi band of 

 the native-type fibril arises by juxtaposition of the a\, a^-j, a'.u and a'4 sites of 

 the TC macromolecule when they are placed in staggered array, obeying the 

 selection rule that adjacent protofibrils are displaced relative to one another by 

 a distance equal to Va of the length of the TC macromolecule in the axial direc- 

 tion. (From Hodge and Schmitt, 1960.) 



action properties of the TC polymers is presumably the result of an 

 altered charge distribution following binding of the strongly nega- 

 tively charged glycoprotein at specific points of the TC. The pres- 

 ence of one exceptionally broad and dense band per period, and 

 relatively few and rather diffuse intraperiod bands, suggests that 

 most of the glvcoprotein is adsorbed near the A and B ends of the 

 TC. This would be in accord with the relatively high concentration 

 of basic groups present in these regions as deduced from the ap- 

 pearance of PTA-stained segments (Figs. 2, 3). 



