N6methyllysine

N6methyllysine, often abbreviated as me6K or N6-MeK, is a post-translational modification found on lysine residues in proteins. This modification involves the addition of a methyl group to the epsilon-amino group of the lysine side chain. N6methyllysine is a common modification that can occur as monomethylation (me1K) or dimethylation (me2K). Trimethylation of lysine also occurs, but is distinct and not typically referred to by the N6methyllysine designation.

This modification is catalyzed by a family of enzymes known as lysine methyltransferases. These enzymes play crucial roles in regulating a wide range of cellular processes. The presence of N6methyllysine can alter the charge and hydrophobicity of the lysine residue, thereby affecting protein-protein interactions, protein-DNA interactions, and protein-ligand binding.

N6methyllysine has been identified in numerous proteins across various cellular compartments, including the nucleus, cytoplasm, and mitochondria. It is particularly well-studied in the context of chromatin regulation, where it can be found on histone proteins. Histone methylation, including N6methyllysine, is a key epigenetic mark that influences gene transcription, DNA repair, and chromosome condensation. Beyond histones, N6methyllysine has also been implicated in the regulation of other proteins involved in metabolism, signaling, and protein degradation. The dynamic nature of lysine methylation, with dedicated methyltransferases and demethylases, allows for fine-tuning of cellular responses.