12. 



Polypoptids S-pJrals . 



If W'3 as sum 2 that th 3 val?nci3S of the 

 carbon ato^ ar3 arrang3d like th s corners of a 

 regular tetrahadroE, and that th 2 three val3nci9S 

 of tri-val ent nitrogen in amino compounds are 

 about 3qual]y distributed around an equatorial 

 circle, (vhich arrangement appears to b :- the 

 only on ^' that is consistent with rill knov/n 

 chemical facts,) then the polypeptide^ chain may 

 be coiled around on itself so as to form a "• 



h el i c al sp i r al h av i ng sub s t an t i al 1 y th 3 s am 3 

 di^jT:]eter as the diketopip erasine ring. 



KO 



^ 



/ 



L J C7/ 



H-N 







\ 



C 



HO 



'/ 



n 



/ \ 



R H 



/ \ 



R K 



A polypeptide spiral in KaCl solu 



