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STRUCTURE OF A DIUBIQUITIN CONJUGATE AND A MODEL FOR INTERACTION WITH UBIQUITIN CONJUGATING ENZYME (E2)STRUCTURE OF A DIUBIQUITIN CONJUGATE AND A MODEL FOR INTERACTION WITH UBIQUITIN CONJUGATING ENZYME (E2)
Structural highlights
FunctionUBC_BOVIN Ubiquitin: Exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCovalent 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. Structure of a diubiquitin conjugate and a model for interaction with ubiquitin conjugating enzyme (E2).,Cook WJ, Jeffrey LC, Carson M, Chen Z, Pickart CM J Biol Chem. 1992 Aug 15;267(23):16467-71. PMID:1322903[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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