K11 Di-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. The abundance of K11 linkages strongly increase when the metazoan anaphase-promoting complex APC/C is active during mitosis, and APC/C has been shown to assemble K11-linked ubiquitin chains to drive proteasomal degradation and exit from mitosis. This K11 linked di-ubiquitin was recombinantly expressed in E. coli, enzymatically conjugated, and purified via liquid chromatography.