Publication Abstract from PubMed
Post-translational modifications involving ubiquitin regulate a wide range of biological processes including protein degradation, responses to DNA damage and immune signalling. Ubiquitin polymerizes into chains which may contain eight different linkage types; the ubiquitin C-terminal glycine can link to one of the seven lysine residues or the N-terminal amino group of methionine in the distal ubiquitin molecule. The latter head-to-tail linkage type, referred to as a linear ubiquitin chain, is involved in NF-kappaB activation through specific interactions with NF-kappaB essential modulator (NEMO). Here, a crystal structure of linear diubiquitin at a resolution of 2.2 A is reported. Although the two ubiquitin moieties do not interact with each other directly, the overall structure adopts a compact but not completely closed conformation with a few intermoiety contacts. This structure differs from the previously reported extended conformation, which resembles Lys63-linked diubiquitin, suggesting that the linear polyubiquitin chain is intrinsically flexible and can adopt multiple conformations.
Structure of a compact conformation of linear diubiquitin.,Rohaim A, Kawasaki M, Kato R, Dikic I, Wakatsuki S Acta Crystallogr D Biol Crystallogr. 2012 Feb;68(Pt 2):102-8. Epub 2012 Jan 13. PMID:22281738[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
