4k7s

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Template:STRUCTURE 4k7s

Contents 1 Crystal structure of Zn2-hUb (human ubiquitin) adduct from a solution 35 mM zinc acetate/1.3 mM hUb 2 Function 3 About this Structure 4 Reference

Crystal structure of Zn2-hUb (human ubiquitin) adduct from a solution 35 mM zinc acetate/1.3 mM hUb

Template:ABSTRACT PUBMED 21268159

Function

[UBC_HUMAN] 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.^{[1] [2]}

About this Structure

4k7s is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

• Arnesano F, Belviso BD, Caliandro R, Falini G, Fermani S, Natile G, Siliqi D. Crystallographic analysis of metal-ion binding to human ubiquitin. Chemistry. 2011 Feb 1;17(5):1569-78. doi: 10.1002/chem.201001617. Epub, 2010 Dec 10. PMID:21268159 doi:10.1002/chem.201001617
• Falini G, Fermani S, Tosi G, Arnesano F, Natile G. Structural probing of Zn(ii), Cd(ii) and Hg(ii) binding to human ubiquitin. Chem Commun (Camb). 2008 Dec 7;(45):5960-2. Epub 2008 Oct 9. PMID:19030552 doi:10.1039/b813463d

1. ↑ Huang F, Kirkpatrick D, Jiang X, Gygi S, Sorkin A. Differential regulation of EGF receptor internalization and degradation by multiubiquitination within the kinase domain. Mol Cell. 2006 Mar 17;21(6):737-48. PMID:16543144 doi:S1097-2765(06)00120-1
2. ↑ Komander D. The emerging complexity of protein ubiquitination. Biochem Soc Trans. 2009 Oct;37(Pt 5):937-53. doi: 10.1042/BST0370937. PMID:19754430 doi:10.1042/BST0370937