M1 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.
K29 linked polyubiquitination has been shown to be an inhibitor of Wnt signaling, which plays an important role in embryogenesis, and its deregulation has been shown to play a role in tumorigenesis. This M1 linked LINEAR tetra-ubiquitin was recombinantly expressed in E. coli, enzymatically conjugated, and purified via liquid chromatography.