View source for 6a44


==R1EN(5-227)-ubiquitin fusion==
<StructureSection load='6a44' size='340' side='right'caption='[[6a44]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6a44]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bombyx_mori Bombyx mori] and [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6A44 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6A44 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]] 2.4&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACY:ACETIC+ACID'>ACY</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=6a44 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6a44 OCA], [https://pdbe.org/6a44 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6a44 RCSB], [https://www.ebi.ac.uk/pdbsum/6a44 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6a44 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/UBC_HUMAN 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.<ref>PMID:16543144</ref> <ref>PMID:19754430</ref> [https://www.uniprot.org/uniprot/Q7M4J4_BOMMO Q7M4J4_BOMMO] 
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== Publication Abstract from PubMed ==
The protein crystallization process requires screening of a large number of conditions using a large quantity of high-purity protein, which makes crystal structure analysis difficult. Thus, the development of easy and versatile protein crystallization techniques is both extremely desirable and highly challenging. Here I demonstrate the crystallization and structure determination of ubiquitin by genetic fusion to the highly porous honeycomb lattice of R1EN. I successfully crystallized and collected X-ray data from three R1EN-ubiquitin constructs with various linker lengths under the same conditions as the original R1EN. The crystals diffracted to 1.7-2.4 A resolution, and the ubiquitin structures were determined with results almost identical to the previously published structure. Moreover, the ubiquitin structure could be solved by molecular replacement using R1EN alone. This method may reduce the effort required for crystallization screening and is applicable to de novo protein structure determination.

Crystal Structure Determination of Ubiquitin by Fusion to a Protein That Forms a Highly Porous Crystal Lattice.,Maita N J Am Chem Soc. 2018 Oct 10. doi: 10.1021/jacs.8b07512. PMID:30299944<ref>PMID:30299944</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6a44" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Bombyx mori]]
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Maita N]]