View source for 5go8


==Linear tetra-ubiquitin==
<StructureSection load='5go8' size='340' side='right'caption='[[5go8]], [[Resolution|resolution]] 2.21&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5go8]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5GO8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5GO8 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.21&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DAL:D-ALANINE'>DAL</scene>, <scene name='pdbligand=DAR:D-ARGININE'>DAR</scene>, <scene name='pdbligand=DAS:D-ASPARTIC+ACID'>DAS</scene>, <scene name='pdbligand=DGL:D-GLUTAMIC+ACID'>DGL</scene>, <scene name='pdbligand=DGN:D-GLUTAMINE'>DGN</scene>, <scene name='pdbligand=DHI:D-HISTIDINE'>DHI</scene>, <scene name='pdbligand=DIL:D-ISOLEUCINE'>DIL</scene>, <scene name='pdbligand=DLE:D-LEUCINE'>DLE</scene>, <scene name='pdbligand=DLY:D-LYSINE'>DLY</scene>, <scene name='pdbligand=DNE:D-NORLEUCINE'>DNE</scene>, <scene name='pdbligand=DPN:D-PHENYLALANINE'>DPN</scene>, <scene name='pdbligand=DPR:D-PROLINE'>DPR</scene>, <scene name='pdbligand=DSG:D-ASPARAGINE'>DSG</scene>, <scene name='pdbligand=DSN:D-SERINE'>DSN</scene>, <scene name='pdbligand=DTH:D-THREONINE'>DTH</scene>, <scene name='pdbligand=DTY:D-TYROSINE'>DTY</scene>, <scene name='pdbligand=DVA:D-VALINE'>DVA</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5go8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5go8 OCA], [https://pdbe.org/5go8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5go8 RCSB], [https://www.ebi.ac.uk/pdbsum/5go8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5go8 ProSAT]</span></td></tr>
</table>
== Function ==
[https://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> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Racemic or quasi-racemic crystallography recently emerges as a useful technology for solution of the crystal structures of biomacromolecules. It remains unclear to what extent the biomacromolecules of opposite handedness can differ from each other in racemic or quasi-racemic crystallography. Here we report a finding that monomeric d-ubiquitin (Ub) has propensity to cocrystallize with different dimers, trimers, and even a tetramer of l-Ub. In these cocrystals the unconnected monomeric d-Ubs can self-assemble to form pseudomirror images of different oligomers of l-Ub. This monomer/oligomer cocrystallization phenomenon expands the concept of racemic crystallography. Using the monomer/oligomer cocrystallization technology we obtained, for the first time the X-ray structures of linear M1-linked tri- and tetra-Ubs and a K11/K63-branched tri-Ub.

Monomer/Oligomer Quasi-Racemic Protein Crystallography.,Gao S, Pan M, Zheng Y, Huang Y, Zheng Q, Sun D, Lu L, Tan X, Tan X, Lan H, Wang J, Wang T, Wang J, Liu L J Am Chem Soc. 2016 Oct 21. PMID:27768314<ref>PMID:27768314</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5go8" style="background-color:#fffaf0;"></div>

==See Also==
*[[3D structures of ubiquitin|3D structures of ubiquitin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Gao S]]
[[Category: Pan M]]
[[Category: Zheng Y]]