Name Symbol Side Chain (pH 7) Side Chain pKa Ave. Comp. (%) % Buried Where will we see it?
Alanine A, Ala -CH3 - 7 51 hydrophobic cores, tight spots
Arginine R, Arg side_arg 12.0 5 5 various polar
Asparagine N, Asn -CH2-CONH2 - 5 22 hydrogen bonds
Aspartic acid D, Asp -CH2-COO- 4.4 5 19 various polar
Cysteine C, Cys -CH2-SH 8.5 2 74 disulfides, active sites
Glutamine Q, Gln -(CH2)2-CONH2 - 4 16 hydrogen bonds
Glutamic acid E, Glu -(CH2)2-COO- 4.4 6 16 various polar
Glycine G, Gly -H - 7 52 left-handed turns, tight places
Histidine* H, His side_his 6.5 2 34 active sites
Isoleucine* I, Ile side_ile - 6 66 hydrophobic cores
Leucine* L, Leu side_leu - 9 60 hydrophobic cores
Lysine* K, Lys -(CH2)4-NH3+ 10.0 6 3 various polar
Methionine* M, Met -(CH2)2-S-CH3 - 2 52 hydrophobic cores
Phenylalanine* F, Phe side_phe - 4 58 hydrophobic cores
Proline P, Pro side_pro - 5 25 N-terminal ends of helices, helix breaker
Serine S, Ser -CH2-OH - 7 35 hydrogen bonds, phosphorylation sites
Threonine* T, Thr side_thr - 6 30 active sites, phosphorylation sites
Tryptophan* W, Trp side_trp - 1 49 hydrophobic cores
Tyrosine Y, Tyr side_tyr 10.0 3 24 active sites, phosphorylation sites
Valine* V, Val 
side_val
 - 6 64 hydrophobic cores

The amino acids names are colored according to their type: positively charged, negatively charged, polar but not charged, aliphatic (nonpolar), and aromatic. Amino acids that are essential to mammals are marked with an asterisk (*).

Suggestions for improvements should be sent to mowbray@xray.bmc.uu.se

Last update: S. Mowbray, 20 August, 2012