title: Structure of a diubiquitin conjugate and a model for interaction with ubiquitin conjugating enzyme (E2).
abstract: Covalent ligation of multiubiquitin chains targets eukaryotic proteins for degradation. In such multiubiquitin chains, successive ubiquitins are linked by an isopeptide bond involving the side chain of Lys48 and the carboxyl group of Gly76. The crystal structure of a diubiquitin conjugate has been determined and refined at 2.3-A resolution. The molecule has internal approximate 2-fold symmetry with multiple hydrophobic and hydrophilic contacts along the 2-fold axis. The structure of the diubiquitin conjugate suggests determinants for recognition of multiubiquitin chains. A model for the interaction of diubiquitin and a ubiquitin conjugating enzyme (E2) is proposed.
authors.affiliation: Department of Pathology, University of Alabama, Birmingham 35294.
authors.forename: W J
authors.initials: WJ
authors.lastname: Cook
authors.forename: L C
authors.initials: LC
authors.lastname: Jeffrey
authors.forename: M
authors.initials: M
authors.lastname: Carson
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.forename: C M
authors.initials: CM
authors.lastname: Pickart
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D008025:Ligases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010944:Plants / Q000201:enzymology; D011485:Protein Binding; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000737:chemistry / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D014452:Ubiquitins; C075986:diubiquitin conjugate; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases