View source for 8i4o


==Design of a split green fluorescent protein for sensing and tracking an beta-amyloid==
<StructureSection load='8i4o' size='340' side='right'caption='[[8i4o]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8i4o]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacteria_Latreille_et_al._1825 Bacteria Latreille et al. 1825]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8I4O OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8I4O 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]] 3.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GYS:[(4Z)-2-(1-AMINO-2-HYDROXYETHYL)-4-(4-HYDROXYBENZYLIDENE)-5-OXO-4,5-DIHYDRO-1H-IMIDAZOL-1-YL]ACETIC+ACID'>GYS</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=8i4o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8i4o OCA], [https://pdbe.org/8i4o PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8i4o RCSB], [https://www.ebi.ac.uk/pdbsum/8i4o PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8i4o ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/A4_HUMAN A4_HUMAN] Defects in APP are the cause of Alzheimer disease type 1 (AD1) [MIM:[https://omim.org/entry/104300 104300]. AD1 is a familial early-onset form of Alzheimer disease. It can be associated with cerebral amyloid angiopathy. Alzheimer disease is a neurodegenerative disorder characterized by progressive dementia, loss of cognitive abilities, and deposition of fibrillar amyloid proteins as intraneuronal neurofibrillary tangles, extracellular amyloid plaques and vascular amyloid deposits. The major constituent of these plaques is the neurotoxic amyloid-beta-APP 40-42 peptide (s), derived proteolytically from the transmembrane precursor protein APP by sequential secretase processing. The cytotoxic C-terminal fragments (CTFs) and the caspase-cleaved products such as C31 derived from APP, are also implicated in neuronal death.<ref>PMID:8476439</ref> <ref>PMID:15201367</ref> <ref>PMID:1671712</ref> <ref>PMID:1908231</ref> <ref>PMID:1678058</ref> <ref>PMID:1944558</ref> <ref>PMID:1925564</ref> <ref>PMID:1415269</ref> <ref>PMID:1303239</ref> <ref>PMID:1302033</ref> <ref>PMID:1303275</ref> <ref>PMID:8267572</ref> <ref>PMID:8290042</ref> <ref>PMID:8577393</ref> <ref>PMID:9328472</ref> <ref>PMID:9754958</ref> <ref>PMID:10097173</ref> <ref>PMID:10631141</ref> <ref>PMID:10665499</ref> <ref>PMID:10867787</ref> <ref>PMID:11063718</ref> <ref>PMID:11311152</ref> <ref>PMID:11528419</ref> <ref>PMID:12034808</ref> <ref>PMID:15365148</ref> <ref>PMID:15668448</ref>   Defects in APP are the cause of cerebral amyloid angiopathy APP-related (CAA-APP) [MIM:[https://omim.org/entry/605714 605714]. A hereditary localized amyloidosis due to amyloid-beta A4 peptide(s) deposition in the cerebral vessels. The principal clinical characteristics are recurrent cerebral and cerebellar hemorrhages, recurrent strokes, cerebral ischemia, cerebral infarction, and progressive mental deterioration. Patients develop cerebral hemorrhage because of the severe cerebral amyloid angiopathy. Parenchymal amyloid deposits are rare and largely in the form of pre-amyloid lesions or diffuse plaque-like structures. They are Congo red negative and lack the dense amyloid cores commonly present in Alzheimer disease. Some affected individuals manifest progressive aphasic dementia, leukoencephalopathy, and occipital calcifications.<ref>PMID:10821838</ref> <ref>PMID:2111584</ref> <ref>PMID:11409420</ref> <ref>PMID:12654973</ref> <ref>PMID:16178030</ref> 
== Function ==
[https://www.uniprot.org/uniprot/A4_HUMAN A4_HUMAN] Functions as a cell surface receptor and performs physiological functions on the surface of neurons relevant to neurite growth, neuronal adhesion and axonogenesis. Involved in cell mobility and transcription regulation through protein-protein interactions. Can promote transcription activation through binding to APBB1-KAT5 and inhibits Notch signaling through interaction with Numb. Couples to apoptosis-inducing pathways such as those mediated by G(O) and JIP. Inhibits G(o) alpha ATPase activity (By similarity). Acts as a kinesin I membrane receptor, mediating the axonal transport of beta-secretase and presenilin 1. Involved in copper homeostasis/oxidative stress through copper ion reduction. In vitro, copper-metallated APP induces neuronal death directly or is potentiated through Cu(2+)-mediated low-density lipoprotein oxidation. Can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I and IV. The splice isoforms that contain the BPTI domain possess protease inhibitor activity. Induces a AGER-dependent pathway that involves activation of p38 MAPK, resulting in internalization of amyloid-beta peptide and leading to mitochondrial dysfunction in cultured cortical neurons. Provides Cu(2+) ions for GPC1 which are required for release of nitric oxide (NO) and subsequent degradation of the heparan sulfate chains on GPC1.<ref>PMID:9168929</ref> <ref>PMID:11544248</ref> <ref>PMID:11943163</ref> <ref>PMID:19225519</ref> <ref>PMID:19901339</ref>   Beta-amyloid peptides are lipophilic metal chelators with metal-reducing activity. Bind transient metals such as copper, zinc and iron. In vitro, can reduce Cu(2+) and Fe(3+) to Cu(+) and Fe(2+), respectively. Beta-amyloid 42 is a more effective reductant than beta-amyloid 40. Beta-amyloid peptides bind to lipoproteins and apolipoproteins E and J in the CSF and to HDL particles in plasma, inhibiting metal-catalyzed oxidation of lipoproteins. Beta-APP42 may activate mononuclear phagocytes in the brain and elicit inflammatory responses. Promotes both tau aggregation and TPK II-mediated phosphorylation. Interaction with Also bind GPC1 in lipid rafts.<ref>PMID:9168929</ref> <ref>PMID:11544248</ref> <ref>PMID:11943163</ref> <ref>PMID:19225519</ref> <ref>PMID:19901339</ref>   Appicans elicit adhesion of neural cells to the extracellular matrix and may regulate neurite outgrowth in the brain (By similarity).<ref>PMID:9168929</ref> <ref>PMID:11544248</ref> <ref>PMID:11943163</ref> <ref>PMID:19225519</ref> <ref>PMID:19901339</ref>   The gamma-CTF peptides as well as the caspase-cleaved peptides, including C31, are potent enhancers of neuronal apoptosis.<ref>PMID:9168929</ref> <ref>PMID:11544248</ref> <ref>PMID:11943163</ref> <ref>PMID:19225519</ref> <ref>PMID:19901339</ref>   N-APP binds TNFRSF21 triggering caspase activation and degeneration of both neuronal cell bodies (via caspase-3) and axons (via caspase-6).<ref>PMID:9168929</ref> <ref>PMID:11544248</ref> <ref>PMID:11943163</ref> <ref>PMID:19225519</ref> <ref>PMID:19901339</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Intrinsically disordered proteins (IDPs) not only play important roles in biological processes but are also linked with the pathogenesis of various human diseases. Specific and reliable sensing of IDPs is crucial for exploring their roles but remains elusive due to structural plasticity. Here, we present the development of a new type of fluorescent protein for the ratiometric sensing and tracking of an IDP. A beta-strand of green fluorescent protein (GFP) was truncated, and the resulting GFP was further engineered to undergo the transition in the absorption maximum upon binding of a target motif within amyloid-beta (Abeta) as a model IDP through rational design and directed evolution. Spectroscopic and structural analyses of the engineered truncated GFP demonstrated that a shift in the absorption maximum is driven by the change in the chromophore state from an anionic (460 nm) state into a neutral (390 nm) state as the Abeta binds, allowing a ratiometric detection of Abeta. The utility of the developed GFP was shown by the efficient and specific detection of an Abeta and the tracking of its conformational change and localization in astrocytes.

Engineering of a Fluorescent Protein for a Sensing of an Intrinsically Disordered Protein through Transition in the Chromophore State.,Yu TG, Lee J, Yoon J, Choi JM, Kim DG, Heo WD, Song JJ, Kim HS JACS Au. 2023 Oct 26;3(11):3055-3065. doi: 10.1021/jacsau.3c00445. eCollection , 2023 Nov 27. PMID:38034956<ref>PMID:38034956</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8i4o" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bacteria Latreille et al. 1825]]
[[Category: Large Structures]]
[[Category: Haksung K]]
[[Category: Jinsu L]]
[[Category: Jungmin C]]
[[Category: Jungmin Y]]
[[Category: Song JJ]]
[[Category: Taegeun Y]]
[[Category: Wondo H]]