Nonpolar amino acids and all characteristics

nonpolar, aliphatic

Methionine Valine Alanine Glycine Leucine Isoleucine Proline

aromatic

Phenylalanine, Tyrosine, Tryptophan

polar, uncharged

Serine, Threonine, Cysteine, Asparagine, Glutamine

positively charged

Lysine, Histidine, Arginine

negatively charged

aspartate, Glutamate

Glycine, Gly, G

characteristic: no optical activity, symmetrical

Alanine, Ala, A

Proline, Pro, P

characteristics: only cyclic structure, 2nd amine

Leucine, Leu, L

Isoleucine, Ile, I

Methionine, Met, M

Characteristics of Nonpolar, aliphatic R groups

The hydrophobic effect stabilizes protein structure

• These amino acids are found clustered in the internal portions of proteins

Characteristics of Aromatic R Groups

absorb UV light at 270 – 280 nm

Characteristic of Polar, Uncharged R Groups

Polar R groups make H-bonds with water

Characteristics of Cysteine/Cystine

readily oxidized to form a disulfide bond

with another cysteine. The covalently linked amino

acids = cystine. This bond is hydrophobic

Characteristics of Positively Charged R Groups

basic amino acids (remove H+ from

solution)

Characteristics of Negatively Charged R Groups

acidic (donate H+ ions to

solution)

Valine, Val, V