Amino acids

structures/abbreviations+properties

Glycine

Gly-G-Hydrophobic and usually resides in forbidden parts of protein structures e.g turns in structures

Alanine

Ala-A-hydrophobic

Valine

Val-V-hydrophobic and aliphatic i.e non polar,not charged and not aromatic

Isoleucine

Ile-I-hydrophobic and aliphatic

Leucine

Leu-L-hydrophobic and aliphatic

Methionine

Met-M-hydrophobic-starts protein chain and 1 of the 2 sulphur containing amino acids but S attached to a methyl group so limited role in function

Serine

Ser-S-polar and uncharged-soluble in water and prefer to be on the surface of proteins

Threonine

Thr-T-polar and uncharged due to functional groups that can form hydrogen bonds

Asparagine

Asn-N-polar and uncharged

Glutamine

Gln-Q-hydrophobic and uncharged

Aspartic Acid

Asp-D-polar and negatively charged

Glutamic Acid

Glu-E-polar and negatively charged - both are acidic due extra carboxyl

Histidine

His-H-imidazole group so polar,basic and positively charged. Fscilitates enzyme catalysed reactions by acting as a proton donor/acceptor due to pKa near physiological pH

Lysine

Lys-K-polar,basic and positively charged due to amino group

Arginine

Arg-R-polar and positively charged+basic due to guanidino group-all polar amino acids that are charged prefer to be on the surface of a protein and if deep in the protein can be used in salt bridges

Phenylalanine

Phe-F-Aromatic and non polar

Tyrosine

Tyr-Y-Aromatic and non-polar but more polar than phenylalanine due to OH group

Tryptophan

Trp-W-Aromatic and non-polar but has indole ring and all aromatic amino acids can absorb ultraviolet light

Proline

Pro-P-distinctive cyclical structure in a rigid conformation reducing flexibility-mostly forms trans peptide bonds , found in turns so mostly on protein surface

Cysteine

Cys-C-can form a dimeric amino acid using disulphide bridge which makes strongly hydrophobic residues and used to form covalent links between parts of a protein or between 2 different polypeptide chains

What are the different types of post-translational modifications?

phosphorylation,hydroxylation,acetylation,methylation,carboxylation,AMPylation,Glycosylation,lipidation,disulphide bond formation,SUMO-ylation,ubiquitylation,proteolysis and deamidation