K48 Tetra-Ubiquitin

The array of cellular processes initiated and regulated by ubiquitin has been partially explained by the structural diversity of differently linked ubiquitin chains. In a ubiquitin chain, ubiquitin moieties can be conjugated through one of their lysine residues (K6, K11, K27, K29, K33, K48 and K63) or the N-terminal methionine residue (M1), offering countless possibilities to assemble a specific polymer. Ubiquitin molecules can also be modified by other post-translational modifications, including acetylation and phosphorylation, adding another layer of ubiquitin signal regulation and diversification. This K48 linked tetra-ubiquitin was recombinantly expressed in E. coli, enzymatically conjugated, and purified via liquid chromatography.