6NK4

KVQIINKKL, crystal structure of a tau protein fragment


Experimental Data Snapshot

  • Method: ELECTRON CRYSTALLOGRAPHY
  • Resolution: 1.99 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.260 
  • R-Value Observed: 0.264 

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This is version 1.3 of the entry. See complete history


Literature

Intrinsic electronic conductivity of individual atomically resolved amyloid crystals reveals micrometer-long hole hopping via tyrosines.

Shipps, C.Kelly, H.R.Dahl, P.J.Yi, S.M.Vu, D.Boyer, D.Glynn, C.Sawaya, M.R.Eisenberg, D.Batista, V.S.Malvankar, N.S.

(2021) Proc Natl Acad Sci U S A 118

  • DOI: https://doi.org/10.1073/pnas.2014139118
  • Primary Citation of Related Structures:  
    6NK4

  • PubMed Abstract: 

    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.


  • Organizational Affiliation

    University of California, Los Angeles-Department of Energy Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095.


Macromolecules

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Microtubule-associated protein tau9Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P10636 (Homo sapiens)
Explore P10636 
Go to UniProtKB:  P10636
GTEx:  ENSG00000186868 
Entity Groups  
UniProt GroupP10636
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON CRYSTALLOGRAPHY
  • Resolution: 1.99 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.260 
  • R-Value Observed: 0.264 
  • Space Group: P 61
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.906α = 90
b = 62.906β = 90
c = 4.832γ = 120
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
DENZOdata reduction
PHASERphasing
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.11.1_2575

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute on Aging (NIH/NIA)United StatesAG0543022

Revision History  (Full details and data files)

  • Version 1.0: 2020-01-15
    Type: Initial release
  • Version 1.1: 2021-01-27
    Changes: Database references
  • Version 1.2: 2021-06-30
    Changes: Data collection
  • Version 1.3: 2023-10-11
    Changes: Data collection, Database references, Refinement description