1. THE PRIMARY STRUCTURES OF PROTEINS
AMINO ACIDS

3. The -carbon is chiral: L and D forms
All protein amino acids are L forms

5. + _

6. Peptide bonds are planar and partially ionic

7. Note the
Directionality:

8. Glycine and alanine have the smallest, simplest side chains.
Both have side chains that are non-polar and neutral.
Hydrophobicity (Go for transfer from butanol to water):

9. Valine, leucine, isoleucine, methionine, and proline are non-polar , neutral, and alaphatic.
Hydrophobicities:

10. Phenylalanine and tryptophan are non-polar, neutral, and aromatic.
Hydrophobicities:

11. Serine, threonine, and tyrosine are polar and neutral.
Hydrophobicities:

12. Cysteine, asparagine, and glutamine are neutral and…
non-polar polar polar.
Hydrophobicities:

13. Lysine, arginine, and histidine are polar and positively charged.
below pH 7)
Hydrophobicities:

14. Aspartate and glutamate are polar and negatively charged.
Hydrophobicities:

15. (Shoulders represent
Transitions) -

16. Titration of a small polypeptide: gly-lys-ala
N C
Note: shoulders in titration curve only for C-term, N-term, and side chains

17. explain the toxicity of some deadly Chinese mushrooms:
There are different, non-protein amino acids. Three amino acids probably
explain the toxicity of some deadly Chinese mushrooms:
2R-amino-4S-hydroxy-5-hexynoic acid;
2R-amino-5-hexynoic acid
gamma-guanidinobutyric acid.
There are different, non-protein amino acids. Science 335: 1293 (12 March 2012): amino acids in mushrooms are probably the deadly toxins: 2R-amino-4S-hydroxy-5-hexyonic acid; 2R-amino-5-hexyonic acid, gamma-guanidinobutyric acid.