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==Crystal structure of Zn1.3-E16V human ubiquitin (hUb) mutant adduct, from a solution 35 mM zinc acetate/1.3 mM E16V hUb== | ==Crystal structure of Zn1.3-E16V human ubiquitin (hUb) mutant adduct, from a solution 35 mM zinc acetate/1.3 mM E16V hUb== | ||
<StructureSection load='5nl4' size='340' side='right' caption='[[5nl4]], [[Resolution|resolution]] 1.32Å' scene=''> | <StructureSection load='5nl4' size='340' side='right'caption='[[5nl4]], [[Resolution|resolution]] 1.32Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[5nl4]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5NL4 OCA]. For a <b>guided tour on the structure components</b> use [ | <table><tr><td colspan='2'>[[5nl4]] is a 3 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=5NL4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5NL4 FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.32Å</td></tr> | ||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[ | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5nl4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5nl4 OCA], [https://pdbe.org/5nl4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5nl4 RCSB], [https://www.ebi.ac.uk/pdbsum/5nl4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5nl4 ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Function == | == 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> | ||
<div style="background-color:#fffaf0;"> | <div style="background-color:#fffaf0;"> | ||
== Publication Abstract from PubMed == | == Publication Abstract from PubMed == | ||
Ubiquitin-positive protein aggregates are biomarkers of neurodegeneration, but the molecular mechanism responsible for their formation and accumulation is still unclear. Possible aggregation pathways of human ubiquitin (hUb) promoted by both intrinsic and extrinsic factors, are here investigated. By a computational analysis, two different hUb dimers are indicated as possible precursors of amyloid-like structures, but their formation is disfavored by an electrostatic repulsion involving Glu16 and other carboxylate residues present at the dimer interface. Experimental data on the E16V mutant of hUb shows that this single-point mutation, although not affecting the overall protein conformation, promotes protein aggregation. It is sufficient to shift the same mutation by only two residues (E18V) to regain the behavior of wild-type hUb. The neutralization of Glu16 negative charge by a metal ion and a decrease of the dielectric constant of the medium by addition of trifluoroethanol (TFE), also promote hUb aggregation. The outcomes of this research have important implications for the prediction of physiological parameters that favor aggregate formation. | |||
Aggregation pathways of native-like ubiquitin promoted by single-point mutation, metal ion concentration and dielectric constant of the medium.,Fermani S, Calvaresi M, Mangini V, Falini G, Bottoni A, Natile G, Arnesano F Chemistry. 2017 Dec 20. doi: 10.1002/chem.201705543. PMID:29266436<ref>PMID:29266436</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | </div> | ||
<div class="pdbe-citations 5nl4" style="background-color:#fffaf0;"></div> | <div class="pdbe-citations 5nl4" style="background-color:#fffaf0;"></div> | ||
==See Also== | |||
*[[3D structures of ubiquitin|3D structures of ubiquitin]] | |||
== References == | == References == | ||
<references/> | <references/> | ||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: | [[Category: Falini G]] | ||
[[Category: | [[Category: Fermani S]] | ||
Latest revision as of 16:04, 15 November 2023
Crystal structure of Zn1.3-E16V human ubiquitin (hUb) mutant adduct, from a solution 35 mM zinc acetate/1.3 mM E16V hUbCrystal structure of Zn1.3-E16V human ubiquitin (hUb) mutant adduct, from a solution 35 mM zinc acetate/1.3 mM E16V hUb
Structural highlights
FunctionUBC_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] Publication Abstract from PubMedUbiquitin-positive protein aggregates are biomarkers of neurodegeneration, but the molecular mechanism responsible for their formation and accumulation is still unclear. Possible aggregation pathways of human ubiquitin (hUb) promoted by both intrinsic and extrinsic factors, are here investigated. By a computational analysis, two different hUb dimers are indicated as possible precursors of amyloid-like structures, but their formation is disfavored by an electrostatic repulsion involving Glu16 and other carboxylate residues present at the dimer interface. Experimental data on the E16V mutant of hUb shows that this single-point mutation, although not affecting the overall protein conformation, promotes protein aggregation. It is sufficient to shift the same mutation by only two residues (E18V) to regain the behavior of wild-type hUb. The neutralization of Glu16 negative charge by a metal ion and a decrease of the dielectric constant of the medium by addition of trifluoroethanol (TFE), also promote hUb aggregation. The outcomes of this research have important implications for the prediction of physiological parameters that favor aggregate formation. Aggregation pathways of native-like ubiquitin promoted by single-point mutation, metal ion concentration and dielectric constant of the medium.,Fermani S, Calvaresi M, Mangini V, Falini G, Bottoni A, Natile G, Arnesano F Chemistry. 2017 Dec 20. doi: 10.1002/chem.201705543. PMID:29266436[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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