Amino Acids Structure

Glycine Gly G

Alanine Ala A

Valine Val V

Leucine Leu L

Isoleucine Ile I

Serine Ser S

Threonine Thr T

Cysteine Cys C

Methionine Met M

Proline Pro P

Phenylalanine Phe F

Tyrosine Tyr Y

Tryptophan Trp W

Aspartic acid Asp D

Glutamic acid Glu E

Asparagine Asn N

Glutamine Gln Q

Lysine Lys K

REQUIRED TO KNOW ON THE EXAM

Arginine Arg R

Histidine His H

Nonpolar AA Side Chains

Aliphatic (hydrocarbon chain) or Aromatic.

R groups with no charge.

Hydrophobic interior residues.

Uncharged Polar AA Side Chains

Hydroxyl, Amide, Phenolic (Aromatic Ring + Hydroxyl), and Thiol.

R groups with no charge but contain a polar functional group.

Hydrophilic residues on protein’s surface.

Charged Polar AA Side Chains

O^-, H₃N⁺, NH⁺₂

R groups with an extra acidic or basic group.

Negatively charged at physiological pH (7.4).

Hydrophilic residues on protein's structure.