View source for 6nk4


==KVQIINKKL, crystal structure of a tau protein fragment==
<StructureSection load='6nk4' size='340' side='right'caption='[[6nk4]], [[Resolution|resolution]] 1.99&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6nk4]] is a 1 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=6NK4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6NK4 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron crystallography, [[Resolution|Resolution]] 1.994&#8491;</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=6nk4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6nk4 OCA], [https://pdbe.org/6nk4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6nk4 RCSB], [https://www.ebi.ac.uk/pdbsum/6nk4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6nk4 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/TAU_HUMAN TAU_HUMAN] Note=In Alzheimer disease, the neuronal cytoskeleton in the brain is progressively disrupted and replaced by tangles of paired helical filaments (PHF) and straight filaments, mainly composed of hyperphosphorylated forms of TAU (PHF-TAU or AD P-TAU). O-GlcNAcylation is greatly reduced in Alzheimer disease brain cerebral cortex leading to an increase in TAU/MAPT phosphorylations.<ref>PMID:19451179</ref> <ref>PMID:2484340</ref> <ref>PMID:14517953</ref>   Defects in MAPT are a cause of frontotemporal dementia (FTD) [MIM:[https://omim.org/entry/600274 600274]; also called frontotemporal dementia (FTD), pallido-ponto-nigral degeneration (PPND) or historically termed Pick complex. This form of frontotemporal dementia is characterized by presenile dementia with behavioral changes, deterioration of cognitive capacities and loss of memory. In some cases, parkinsonian symptoms are prominent. Neuropathological changes include frontotemporal atrophy often associated with atrophy of the basal ganglia, substantia nigra, amygdala. In most cases, protein tau deposits are found in glial cells and/or neurons.<ref>PMID:19451179</ref> <ref>PMID:2484340</ref> <ref>PMID:14517953</ref> <ref>PMID:9629852</ref> <ref>PMID:9736786</ref> <ref>PMID:9641683</ref> <ref>PMID:9789048</ref> <ref>PMID:9973279</ref> <ref>PMID:10553987</ref> <ref>PMID:10214944</ref> <ref>PMID:10374757</ref> <ref>PMID:10489057</ref> <ref>PMID:10208578</ref> <ref>PMID:11117541</ref> <ref>PMID:10802785</ref> <ref>PMID:11071507</ref> <ref>PMID:11585254</ref> <ref>PMID:11278002</ref> <ref>PMID:12473774</ref> <ref>PMID:11921059</ref> <ref>PMID:11906000</ref> <ref>PMID:11889249</ref> <ref>PMID:12509859</ref> <ref>PMID:16240366</ref> <ref>PMID:15883319</ref>   Defects in MAPT are a cause of Pick disease of the brain (PIDB) [MIM:[https://omim.org/entry/172700 172700]. It is a rare form of dementia pathologically defined by severe atrophy, neuronal loss and gliosis. It is characterized by the occurrence of tau-positive inclusions, swollen neurons (Pick cells) and argentophilic neuronal inclusions known as Pick bodies that disproportionally affect the frontal and temporal cortical regions. Clinical features include aphasia, apraxia, confusion, anomia, memory loss and personality deterioration.<ref>PMID:19451179</ref> <ref>PMID:2484340</ref> <ref>PMID:14517953</ref> <ref>PMID:10604746</ref> <ref>PMID:11117542</ref> <ref>PMID:11089577</ref> <ref>PMID:11601501</ref> <ref>PMID:11891833</ref>   Note=Defects in MAPT are a cause of corticobasal degeneration (CBD). It is marked by extrapyramidal signs and apraxia and can be associated with memory loss. Neuropathologic features may overlap Alzheimer disease, progressive supranuclear palsy, and Parkinson disease.<ref>PMID:19451179</ref> <ref>PMID:2484340</ref> <ref>PMID:14517953</ref>   Defects in MAPT are a cause of progressive supranuclear palsy type 1 (PSNP1) [MIM:[https://omim.org/entry/601104 601104]; also abbreviated as PSP and also known as Steele-Richardson-Olszewski syndrome. PSNP1 is characterized by akinetic-rigid syndrome, supranuclear gaze palsy, pyramidal tract dysfunction, pseudobulbar signs and cognitive capacities deterioration. Neurofibrillary tangles and gliosis but no amyloid plaques are found in diseased brains. Most cases appear to be sporadic, with a significant association with a common haplotype including the MAPT gene and the flanking regions. Familial cases show an autosomal dominant pattern of transmission with incomplete penetrance; genetic analysis of a few cases showed the occurrence of tau mutations, including a deletion of Asn-613.<ref>PMID:19451179</ref> <ref>PMID:2484340</ref> <ref>PMID:14517953</ref> <ref>PMID:10534245</ref> <ref>PMID:11220749</ref> <ref>PMID:12325083</ref> <ref>PMID:14991829</ref> <ref>PMID:14991828</ref> <ref>PMID:16157753</ref>   Defects in MAPT are a cause of Parkinson-dementia syndrome (PARDE) [MIM:[https://omim.org/entry/260540 260540]. A syndrome characterized by parkinsonism tremor, rigidity, dementia, ophthalmoparesis and pyramidal signs. Neurofibrillary degeneration occurs in the hippocampus, basal ganglia and brainstem nuclei.<ref>PMID:19451179</ref> <ref>PMID:2484340</ref> <ref>PMID:14517953</ref> 
== Function ==
[https://www.uniprot.org/uniprot/TAU_HUMAN TAU_HUMAN] Promotes microtubule assembly and stability, and might be involved in the establishment and maintenance of neuronal polarity. The C-terminus binds axonal microtubules while the N-terminus binds neural plasma membrane components, suggesting that tau functions as a linker protein between both. Axonal polarity is predetermined by TAU/MAPT localization (in the neuronal cell) in the domain of the cell body defined by the centrosome. The short isoforms allow plasticity of the cytoskeleton whereas the longer isoforms may preferentially play a role in its stabilization.<ref>PMID:21985311</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Proteins are commonly known to transfer electrons over distances limited to a few nanometers. However, many biological processes require electron transport over far longer distances. For example, soil and sediment bacteria transport electrons, over hundreds of micrometers to even centimeters, via putative filamentous proteins rich in aromatic residues. However, measurements of true protein conductivity have been hampered by artifacts due to large contact resistances between proteins and electrodes. Using individual amyloid protein crystals with atomic-resolution structures as a model system, we perform contact-free measurements of intrinsic electronic conductivity using a four-electrode approach. We find hole transport through micrometer-long stacked tyrosines at physiologically relevant potentials. Notably, the transport rate through tyrosines (10(5) s(-1)) is comparable to cytochromes. Our studies therefore show that amyloid proteins can efficiently transport charges, under ordinary thermal conditions, without any need for redox-active metal cofactors, large driving force, or photosensitizers to generate a high oxidation state for charge injection. By measuring conductivity as a function of molecular length, voltage, and temperature, while eliminating the dominant contribution of contact resistances, we show that a multistep hopping mechanism (composed of multiple tunneling steps), not single-step tunneling, explains the measured conductivity. Combined experimental and computational studies reveal that proton-coupled electron transfer confers conductivity; both the energetics of the proton acceptor, a neighboring glutamine, and its proximity to tyrosine influence the hole transport rate through a proton rocking mechanism. Surprisingly, conductivity increases 200-fold upon cooling due to higher availability of the proton acceptor by increased hydrogen bonding.

Intrinsic electronic conductivity of individual atomically resolved amyloid crystals reveals micrometer-long hole hopping via tyrosines.,Shipps C, Kelly HR, Dahl PJ, Yi SM, Vu D, Boyer D, Glynn C, Sawaya MR, Eisenberg D, Batista VS, Malvankar NS Proc Natl Acad Sci U S A. 2021 Jan 12;118(2). pii: 2014139118. doi:, 10.1073/pnas.2014139118. PMID:33372136<ref>PMID:33372136</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6nk4" style="background-color:#fffaf0;"></div>

==See Also==
*[[Microtubule-associated protein 3D structures|Microtubule-associated protein 3D structures]]
*[[Tau protein 3D structures|Tau protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Boyer DR]]
[[Category: Eisenberg DS]]
[[Category: Sawaya MR]]