Segmental Isotopic Labeling of Ubiquitin Chains To Unravel Monomer-Specific Molecular Behavior

摘要

Ubiquitination, the attachment of the 76 aa protein ubiquitin (Ub) or of a polyubiquitin (polyUb) chain to a protein target, is involved in a wide range of cellular processes in eukaryotes, ranging from progression through the cell cycle to transcriptional activation, antigen processing, and vesicular trafficking of proteins. Ub monomers are usually linked to each other by an isopeptide bond between the e-amino group of a lysine residue in the proximal Ub and the C-terminal Gly76 of the successive Ub also known as the distal Ub. Thanks to the seven lysines in the Ub sequence, polyUb chains can be formed of various linkages and lengths (e.g. [2]).