AMINO ACID R GROUPS

Glycine (Gly/G)

Nonpolar, Hydrophobic: Hydrogen atom, smallest amino acid, achiral

Alanine (Ala/A)

Nonpolar, Hydrophobic: Methyl group

Valine (Val/V)

Nonpolar, Hydrophobic: Isopropyl group

Leucine (Leu/L)

Nonpolar, Hydrophobic: Isobutyl group

Isoleucine (Leu/L)

Nonpolar, Hydrophobic: sec-butyl group

Proline (Pro/P)

Nonpolar, Hydrophobic: R group forms a ring with the rigid backbone of the nitrogen, creating a rigid structure

Methionine (Met/M)

Nonpolar, Hydrophobic: R group contains a thioether group (-CH2-CH2-S-CH3)

Phenylalanine (Phe/F)

Nonpolar, Hydrophobic: R group contains a benzyl/aromatic ring

Tryptophan (Trp/W)

Nonpolar, Hydrophobic: R group contains a bulky indole ring

Serine (Ser/S)

Polar, Uncharged: R group contains a hydroxyl group (-CH2-OH)

Threonine (Thr/T)

Polar, Uncharged: R groups contains a hydroxyl group (-CH(OH)-CH3)

Cysteine (Cys/C)

Polar, Uncharged: R group contains a thiol group (-CH2-SH) which can form disulfide bonds

Asparagine (Asn/N)

Polar, Uncharged: R group contains an amide group

Glutamine (Gln, Q)

Polar, Uncharged: R group contains an extended amide group

Tyrosine (Tyr/Y)

Polar, Uncharged: R group contains a phenolic ring, making it polar and aromatic

Aspartic Acid/ Asparate (Asp/D)

Negatively Charged (Acidic): R group has a carboxylate group (-CH2-COO^-)

Glutamic Acid/ Glutamate (Glu/E)

Negatively Charged (Acidic): R group has an extended carboxylate group (-CH2-CH2-COO^-)

Lysine (Lys/K)

Positively Charged (Basic): R group ends with a primary amino group (-(CH2)4-NH3^+)

Arginine (Arg/R)

Positively Charged (Basic): R group contains a guanidino group, which stays strongly basic

Histidine (His/H)

Positively Charged (Basic): R group contains an imidazole ring that can act as a proton donor or acceptor near neutral pH