Poly-ubiquitination of target proteins through K63 has recently become the focus of intense study. The topology of this linkage type is quite different from polyubiquitin linked through lysine 48. Modification of proteins by K63-linked poly-ubiquitination has been implicated in, among other cellular processes, the regulation of the DNA damage response, endosomal sorting, autophagy of misfolded/aggregated proteins, neurodegeneration, and signal transduction. Tetraubiquitin chains are generated from the enzymatic linkage of wild-type ubiquitin through lysine 63. The most distal ubiquitin contains an arginine substitution for the lysine at position 63, limiting chain length.
|20 mM Tris pH 7.5, 150 mM NaCl, 1 mM EDTA
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