Polyglutamylation

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A form of reversible posttranslational modification of glutamate residues seen for example in alpha and beta tubulins, nucleosome assembly proteins NAP1 and NAP2. The Gamma carboxy group of glutamate may form peptide like bond with the Amino group of a free glutamate whose alpha carboxy group can now be extended into a polyglutamate chain[1]. The glutamylation is done by the enzyme glutamylase and removed by deglutamylase

Polyglutamylation of chain length of upto six occurs in certain glutamate residues near the C terminus of most major forms of tubulins. These residues, though themselves not involved in direct binding, cause conformational shifts that regulate binding of microtubule associated proteins (MAP and Tau) and motors[1].

[edit] External links

Polyglutamylases:_a_divergent_group_of_modifying_enzymes

[edit] References

  1. ^ Boucher, D., Larcher, J. C., Gros, F. and Denoulet, P (1994). Polyglutamylation of tubulin as a progressive regulator of in vitro interactions between the microtubule-associated protein Tau and tubulin. Biochemistry 33, 12471-12477 Pubmed_abstract


Protein primary structure and posttranslational modifications
General: Protein biosynthesis | Peptide bond | Proteolysis | Racemization | N-O acyl shift
N-terminus: Acetylation | Formylation | Myristoylation | Pyroglutamate | methylation | glycation | myristoylation (Gly) | carbamylation
C-terminus: Amidation | Glycosyl phosphatidylinositol (GPI) | O-methylation | glypiation | ubiquitination | sumoylation
Lysine: Methylation | Acetylation | Acylation | Hydroxylation | Ubiquitination | SUMOylation | Desmosine | deamination and oxidation to aldehyde| O-glycosylation | imine formation | glycation | carbamylation
Cysteine: Disulfide bond | Prenylation | Palmitoylation
Serine/Threonine: Phosphorylation | Glycosylation
Tyrosine: Phosphorylation | Sulfation | porphyrin ring linkage | flavin linkage | GFP prosthetic group (Thr-Tyr-Gly sequence) formation | Lysine tyrosine quinone (LTQ) formation | Topaquinone (TPQ) formation
Asparagine: Deamidation | Glycosylation
Aspartate: Succinimide formation
Glutamine: Transglutamination
Glutamate: Carboxylation | polyglutamylation | polyglycylation
Arginine: Citrullination | Methylation
Proline: Hydroxylation
←Amino acids Secondary structure→