276 



X-ray Analyses of Proteins and Nucleic Acids /1 5 : 2 



Amino Acid 



Structure 



Abbreviation 

 Molecular for residue 

 weight in proteins 



10. Tryptophan 



204 



-try- 



1 1 . Cysteine 



11a. Cystine 



H O 



I / 

 CH 2 — C— C 



I I \ 



HS NH 2 OH 



HO H 



H O 



/ 



C — C CH 2 GH 2 — C — C 



/"III I \ 



O NH 2 S S NH 2 OH 



H O 



I / 

 12. Methionine CH 2 — CH 2 — C— C 



I I \ 



CH 3 — S NH 2 OH 



HO 



13. Aspartic Acid 



H O 



O 



HO 



/ 



C— CH 2 — C— C 



NH 2 OH 



14. Glutamic Acid 



H O 



O 



/" 



C — CH 2 — CH 2 — C — C 



NH 2 OH 



15. Lysine 



16. Arginine 



H O 



I /- 

 CH 2 — CH 2 — CH 2 — CH 2 — C — C 



NH 2 NH 2 OH 



H O 



I / 

 CH 2 — ■CH 2 — CH 2 — C — C 



I I \ 



H 2 N— C— NH NH 2 OH 



NH 



121 



240 



135 



133 



163 



146 



174 



SH 



I 

 — cy— 



— cy— 



I 

 S 



I 



s 



— cy— 

 — met— 



-asp — 



— glu — 



— lys — 



-arg- 



