M1-linked Tetra-Ubiqutin (human) (rec.) (untagged)

Recombinant Protein. Four enzymatically conjugated linear human ubiquitin (aa1-76) covalently linked through an isopeptide bond at M1 residue of one ubiquitin molecule and the C-terminal glycine residue of another ubiquitin molecule and untagged. Source/Host: E. coli. Liquid. In 50mM HEPES pH 7.5. 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. M1-linked chains play critical roles in inflammatory and immune responses by regulating the activation of NF-kappaB. Activated cytokine receptors and toll-like receptors (TLRs) recruiting e.g. kinases and E3 ubiquitin ligases, and resultant phosphorylation and ubiquitylation lead to the activation of effector proteins. This protein is formed with wild-type human recombinant ubiquitin and linkage-specific enzymes. Ideal for investigating ubiquitin-binding proteins and as substrates for ubiquitin-specific isopeptidases. Reaction conditions will need to be optimized for each specific application.