Lysine reversible modification

Pathy, L., and Smith, E.L. (1975) Reversible modification of arginine residues Application to sequence studies by restriction of tryptic hydrolysis to lysine residues./. Biol. Chem. 250, 557. 

Shetty, J.K., and Kinsella, J.E. (1980) Ready separation of proteins from nucleoprotein complexes by reversible modification of lysine residues. Biochem. J. 191, 269-272. 

Acetylation is a reversible modification on proteins that can also contribute to protein localization and function. Acetylation of lysine residues in histone proteins can control the secondary structure of chromatin as well as gene expression levels from certain loci, and chromatin remodeling and its consequences in a variety of molecular and cell biological questions are intensely researched. Many other proteins undergo reversible acetylation, and the functional consequences of these modifications are poorly understood in many cases. 

Reversible Modification of Amino Groups of Lysine in Yeast Proteins Using Citraconic and Maleic Anhydrides... 

Protein phosphorylation is a pervasive posttranslational modification in cells. It is reversible and can dramatically affect the activity of a modified protein. Protein phosphorylation is one of the most important mechanisms used for signal transduction by cells. In prokaryotic cells, the best-known reversible protein phosphorylations occur on histidine and aspartate in eukaryotes the best-known occur on the hydroxyl groups of serine, threonine, and tyrosine, although histidine can also be phosphorylated (Fig. 3.9). Other reversible modifications also occur, such as the acetylation of lysine residues in histone proteins. 

ADP—ribosyltransferases modify the activity of target enzymes by catalysing the transfer of ADP—ribose onto arginine, lysine or asparagine residues. ADP—ribosylation is a reversible modification of proteins, and there are specific hydrolases which cleave the N-glycoside linkage. 

Althongh the isoprenoid moiety is essential for localization, it is nsnally not enongh for ensuring stable membrane association. In the case of the K-Ras isoform, this is achieved by a polybasic seqnence formed by eight lysines, which specifically interact with the acidic phospholipids present at the membrane. In some other cases, snch as the N-Ras or H-Ras isoforms, a second lipidation motif is necessary, and these proteins are subsequently palmi-toylated at cysteine residnes located near the prenylated cysteine. The palmitoylation of cysteines is a reversible modification catalyzed by protein acyltransferases (PATs) and by acyl protein thioes-terases (APTs) (Fig. 1) [9]. 

Histone acetylation is a reversible and covalent modification of histone proteins introduced at the e-amino groups of lysine residues. Histones and DNA form a complex - chromatin - which condenses DNA and controls gene activity. Current models interpret histone acetylation as a means to regulate chromatin activity. 

Histone methylation is a common posttranslational modification fond in histones. Histone methylations have been identified on lysine and arginine residues. In case of lysines S-adenosyl-methionine (SAM) dependent methyl transferases catalyze the transfer of one, two or three methyl groups. Lysine methylation is reversible and lysine specific demethylases have been... 

Many recent studies have focused on the mechanisms of formaldehyde modification, cross-linking, and reversal.19,37 8 In general, these studies found that formaldehyde is very specific, particularly when reaction times are relatively short. The amino-termini, lysine, tryptophan, and cysteine are the targets of modification in this case. Longer reaction times reveal more extensive modifications, including arginine, histidine, tyrosine, and phenylalanine. 

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