View source for 6jb7


==Crystal structure of Ub-conjugated Ube2K C92K&K97A mutant (isopeptide linkage), 2.1 A resolution==
<StructureSection load='6jb7' size='340' side='right'caption='[[6jb7]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6jb7]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6JB7 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6JB7 FirstGlance]. <br>
</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/E2_ubiquitin-conjugating_enzyme E2 ubiquitin-conjugating enzyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.2.23 2.3.2.23] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6jb7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6jb7 OCA], [http://pdbe.org/6jb7 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6jb7 RCSB], [http://www.ebi.ac.uk/pdbsum/6jb7 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6jb7 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/UBB_HUMAN UBB_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.<ref>PMID:16543144</ref> <ref>PMID:19754430</ref>  [[http://www.uniprot.org/uniprot/UBE2K_HUMAN UBE2K_HUMAN]] Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro, in the presence or in the absence of BRCA1-BARD1 E3 ubiquitin-protein ligase complex, catalyzes the synthesis of 'Lys-48'-linked polyubiquitin chains. Does not transfer ubiquitin directly to but elongates monoubiquitinated substrate protein. Mediates the selective degradation of short-lived and abnormal proteins, such as the endoplasmic reticulum-associated degradation (ERAD) of misfolded lumenal proteins. Ubiquitinates huntingtin. May mediate foam cell formation by the suppression of apoptosis of lipid-bearing macrophages through ubiquitination and subsequence degradation of p53/TP53. Proposed to be involved in ubiquitination and proteolytic processing of NF-kappa-B; in vitro supports ubiquitination of NFKB1. In case of infection by cytomegaloviruses may be involved in the US11-dependent degradation of MHC class I heavy chains following their export from the ER to the cytosol. In case of viral infections may be involved in the HPV E7 protein-dependent degradation of RB1.<ref>PMID:8702625</ref> <ref>PMID:10634809</ref> <ref>PMID:10675012</ref> <ref>PMID:16714285</ref> <ref>PMID:16868077</ref> <ref>PMID:17873885</ref> <ref>PMID:20061386</ref> <ref>PMID:19906396</ref>  
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: E2 ubiquitin-conjugating enzyme]]
[[Category: Large Structures]]
[[Category: An, J Y]]
[[Category: Eom, S H]]
[[Category: Jin, M W]]
[[Category: Kang, J Y]]
[[Category: Lee, J G]]
[[Category: Lee, Y]]
[[Category: Mun, S A]]
[[Category: Park, J]]
[[Category: Park, K R]]
[[Category: Park, T]]
[[Category: Yang, J]]
[[Category: Youn, H S]]
[[Category: Complex]]
[[Category: Ligase]]