Protein methylation is among the most common and important post-translational modifications and plays a major role in several biological processes, including signal transduction, DNA repairing, transcriptional regulation, gene activation, gene repression and RNA processing1. It involves the covalent attachment of a methyl group onto the C-terminus, N-terminus or one of eight amino acid residues. These […]
Posts with the Post-translational modification tag
Acylation
Protein acylation refers to all modifications that covalently bind acyl groups to a protein. Acylation occurs in all living organisms and is carried out by specific acyl transferases. The structure and size of the acyl groups varies greatly, from small moieties such as acetate to long chain fatty acids such as palmitic acid. The moieties […]
γ-Carboxylation
Overview γ-Carboxylation occurs mainly in proteins related to blood coagulation. Glutamic acid residues are carboxylated by the enzyme glutamyl carboxylase in γ-position in the presence of oxygen and carbon dioxide. Vitamin K is required as a cofactor. pKa NC Loss Gain Deltamass H AA UV-Spec Pattern Acidic 2.03 Yes H CHO2 Av: 44.0095M: 43.9898 – […]
S-Nitrosylation
Overview S-Nitrosylation is a post-translational modification in which a nitric oxide molecule is bound via a reactive thiol group of a cysteine residue. S-nitrosylation has various regulatory roles in bacteria, yeasts, plants and mammalian cells. pKa NC Loss Gain Deltamass H AA UV-Spec Pattern – No H NO Av: 28.9982M: 28.9902 – C Yes – […]
ADP-Ribosylation
ADP-ribosylation is a reversible post-translational modification in which one (mono-ADP-ribosylation) or multiple (poly-ADP-ribosylation) ADP-ribose moieties are attached onto a substrate protein by ADP ribosyltransferases. mono-ADP-Ribosylation Overview mono-ADP-ribosylation is a common post-translational modification, where an ADP-ribose moiety is transferred from NAD+ to the substrate protein under the release of nicotinamide. The transfer of ADP-ribose occurs onto […]
Citrullination
Overview Citrulline is a non-proteinogenic amino acid that is produced through post-translational deimination of peptidyl-arginine. Peptidyl-arginine deiminases catalyze the hydrolysis of a guanido group into an urea group. This modifications affects the formation of hydrogen bonds and therefore protein folding. pKa NC Loss Gain Deltamass H AA UV-Spec Pattern – No NH O Av: 0.9848M: […]
Prenylation
Prenylation covers two post-translational modifications in which one or two isoprenoid moieties, either farnesyl or geranylgeranyl moieties, are attached to a conserved cysteine residue via thioether bond at or near the C-terminus. Most prenylated proteins contain a CAAX motif at the C-terminus. The CAAX motif is a sequence of four amino acids, where “C” stands […]
O-Sulfation
Overview O-Sulfation is a common post-translational modification of tyrosine residues in eukaryotes, but has not been observed in yeast and prokaryotes. Sulfation is limited to secretory and trans-membrane proteins that have passed the trans-Golgi network, where two membrane-bound tyrosylprotein sulfotransferase enzymes catalyze the transfer of sulfate from adenosine 3’-phosphate5’-phosphosulfate to the tyrosine phenol. pKa NC […]
Nitration
Overview Nitration is a post-translational modification of mostly tyrosine residues that is caused by one-electron oxidation. First, a tyrosine radical is formed by one-electron oxidation followed by a reaction with nitrogen dioxide resulting in 3-nitrotyrosine. pKa NC Loss Gain Deltamass H AA UV-Spec Pattern Acidic7.25 No H NO2 Av: 44.9976M: 44.9851 – Y Yes* – […]
Amidation
Amidation is one of the most common post-translational modification in which the C-terminal carboxyl group is replaced by an amide group1–5. Amidation plays an important role in peptidesand peptide hormones. More than half of all mammalian peptide hormones and more than 80 % of all insect hormones have amidated C-termini1. The mechanism of amidation is […]