scholarly journals The molecular mechanism of Hsp90-induced oligomerization of Tau

2019 ◽  
Author(s):  
Sabrina Weickert ◽  
Magdalena Wawrzyniuk ◽  
Laura John ◽  
Stefan G. D. Rüdiger ◽  
Malte Drescher
Keyword(s):  
Structural Information ◽  
Conformational Ensemble ◽  
Toxic Agent ◽  
Paramagnetic Resonance ◽  
Biologically Relevant ◽  
Intrinsically Disordered ◽  
Tau Oligomers ◽  
Paper Clip ◽  
Repeat Domain ◽  
Electron Paramagnetic

AbstractAggregation of the microtubule-associated protein Tau is a hallmark of Alzheimer’s disease with Tau oligomers suspected as the most toxic agent. Tau is a client of Hsp90, though it is unclear whether and how the chaperone massages the structure of intrinsically disordered Tau. Using electron paramagnetic resonance, we extract structural information from the very broad conformational ensemble of Tau: Tau in solution is highly dynamic and polymorphic, though ‘paper-clip’-shaped by long-range contacts. Interaction with Hsp90 promotes an open Tau conformation, which we identify as the molecular basis for the formation of small Tau oligomers by exposure of the aggregation-prone repeat domain to other Tau molecules. At the same time, formation of Tau fibrils is inhibited. We therefore provide the nanometer-scale zoom into chaperoning an amyloid client, highlighting formation of oligomers as the consequence of this biologically relevant interaction.

scholarly journals The mechanism of Hsp90-induced oligomerizaton of Tau

2020 ◽  
Vol 6 (11) ◽  
pp. eaax6999 ◽  
Author(s):  
S. Weickert ◽  
M. Wawrzyniuk ◽  
L. H. John ◽  
S. G. D. Rüdiger ◽  
M. Drescher
Keyword(s):  
Structural Information ◽  
Conformational Ensemble ◽  
Toxic Agent ◽  
Paramagnetic Resonance ◽  
Biologically Relevant ◽  
Intrinsically Disordered ◽  
Tau Oligomers ◽  
Paper Clip ◽  
Repeat Domain ◽  
Electron Paramagnetic

Aggregation of the microtubule-associated protein Tau is a hallmark of Alzheimer’s disease with Tau oligomers suspected as the most toxic agent. Tau is a client of the molecular chaperone Hsp90, although it is unclear whether and how the chaperone massages the structure of intrinsically disordered Tau. Using electron paramagnetic resonance, we extract structural information from the very broad conformational ensemble of Tau: Tau in solution is highly dynamic and polymorphic, although “paper clip”–shaped by long-range contacts. Interaction with Hsp90 promotes an open Tau conformation, which we identify as the molecular basis for the formation of small Tau oligomers by exposure of the aggregation-prone repeat domain to other Tau molecules. At the same time, formation of Tau fibrils is inhibited. We therefore provide the nanometer-scale zoom into chaperoning an amyloid client, highlighting formation of oligomers as the consequence of this biologically relevant interaction.

scholarly journals Spin-labeled nanobodies as protein conformational reporters for electron paramagnetic resonance in cellular membranes

2020 ◽  
Vol 117 (5) ◽  
pp. 2441-2448 ◽  
Author(s):  
Laura Galazzo ◽  
Gianmarco Meier ◽  
M. Hadi Timachi ◽  
Cedric A. J. Hutter ◽  
Markus A. Seeger ◽  
...  
Keyword(s):  
Structural Biology ◽  
Structural Information ◽  
Modulation Depth ◽  
Conformational Dynamics ◽  
Conformational Ensemble ◽  
Wild Type ◽  
Cellular Membranes ◽  
Experimental Conditions ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

Nanobodies are emerging tools in a variety of fields such as structural biology, cell imaging, and drug discovery. Here we pioneer the use of their spin-labeled variants as reporters of conformational dynamics of membrane proteins using DEER spectroscopy. At the example of the bacterial ABC transporter TM287/288, we show that two gadolinium-labeled nanobodies allow us to quantify, via analysis of the modulation depth of DEER traces, the fraction of transporters adopting the outward-facing state under different experimental conditions. Additionally, we quantitatively follow the interconversion from the outward- to the inward-facing state in the conformational ensemble under ATP turnover conditions. We finally show that the specificity of the nanobodies for the target protein allows the direct attainment of structural information on the wild-type TM287/288 expressed in cellular membranes without the need to purify or label the investigated membrane protein.

scholarly journals 2′-Alkynyl spin-labelling is a minimally perturbing tool for DNA structural analysis

2020 ◽  
Vol 48 (6) ◽  
pp. 2830-2840 ◽  
Author(s):  
Jack S Hardwick ◽  
Marius M Haugland ◽  
Afaf H El-Sagheer ◽  
Denis Ptchelkine ◽  
Frank R Beierlein ◽  
...  
Keyword(s):  
Epr Spectroscopy ◽  
Spin Labels ◽  
Resonance Spectroscopy ◽  
Conformational Ensemble ◽  
Dna Duplexes ◽  
Paramagnetic Resonance ◽  
Dynamics Simulations ◽  
Electron Paramagnetic ◽  
Spin Labelling

Abstract The determination of distances between specific points in nucleic acids is essential to understanding their behaviour at the molecular level. The ability to measure distances of 2–10 nm is particularly important: deformations arising from protein binding commonly fall within this range, but the reliable measurement of such distances for a conformational ensemble remains a significant challenge. Using several techniques, we show that electron paramagnetic resonance (EPR) spectroscopy of oligonucleotides spin-labelled with triazole-appended nitroxides at the 2′ position offers a robust and minimally perturbing tool for obtaining such measurements. For two nitroxides, we present results from EPR spectroscopy, X-ray crystal structures of B-form spin-labelled DNA duplexes, molecular dynamics simulations and nuclear magnetic resonance spectroscopy. These four methods are mutually supportive, and pinpoint the locations of the spin labels on the duplexes. In doing so, this work establishes 2′-alkynyl nitroxide spin-labelling as a minimally perturbing method for probing DNA conformation.

The electron paramagnetic resonance of methylene

1984 ◽  
Vol 62 (12) ◽  
pp. 1724-1730 ◽  
Author(s):  
R. A. Bernheim
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Bond Angle ◽  
Structural Information ◽  
Zero Field ◽  
Paramagnetic Resonance ◽  
Structure Splitting ◽  
Parameters Measurement ◽  
Laser Magnetic Resonance ◽  
Electron Paramagnetic ◽  
Electronic Ground

The electron paramagnetic resonance studies of methylene arc reviewed. The structural information that resulted include verification of the triplet multiplicity of the electronic ground state, the discovery of a bent geometry for the molecule with a bond angle of 134°, measurement of the zero-field or fine-structure splitting parameters, measurement of the g-factor tensor, and measurement of the isotropic and anisotropic 13C hyperfine interaction. The results are compared with recent measurements obtained with laser magnetic resonance techniques and theoretical treatments.

scholarly journals Recent Advances in Computational Protocols Addressing Intrinsically Disordered Proteins

Biomolecules ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 146 ◽  
Author(s):  
Supriyo Bhattacharya ◽  
Xingcheng Lin
Keyword(s):  
Single Molecule ◽  
Degrees Of Freedom ◽  
Intrinsically Disordered Proteins ◽  
Structural Information ◽  
Conformational Dynamics ◽  
Resonance Energy ◽  
Structural Data ◽  
Disordered Proteins ◽  
Conformational Ensemble ◽  
Intrinsically Disordered

Intrinsically disordered proteins (IDP) are abundant in the human genome and have recently emerged as major therapeutic targets for various diseases. Unlike traditional proteins that adopt a definitive structure, IDPs in free solution are disordered and exist as an ensemble of conformations. This enables the IDPs to signal through multiple signaling pathways and serve as scaffolds for multi-protein complexes. The challenge in studying IDPs experimentally stems from their disordered nature. Nuclear magnetic resonance (NMR), circular dichroism, small angle X-ray scattering, and single molecule Förster resonance energy transfer (FRET) can give the local structural information and overall dimension of IDPs, but seldom provide a unified picture of the whole protein. To understand the conformational dynamics of IDPs and how their structural ensembles recognize multiple binding partners and small molecule inhibitors, knowledge-based and physics-based sampling techniques are utilized in-silico, guided by experimental structural data. However, efficient sampling of the IDP conformational ensemble requires traversing the numerous degrees of freedom in the IDP energy landscape, as well as force-fields that accurately model the protein and solvent interactions. In this review, we have provided an overview of the current state of computational methods for studying IDP structure and dynamics and discussed the major challenges faced in this field.

scholarly journals Gd3+–Gd3+ distances exceeding 3 nm determined by very high frequency continuous wave electron paramagnetic resonance

2017 ◽  
Vol 19 (7) ◽  
pp. 5127-5136 ◽  
Author(s):  
Jessica A. Clayton ◽  
Mian Qi ◽  
Adelheid Godt ◽  
Daniella Goldfarb ◽  
Songi Han ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Very High Frequency ◽  
Fundamental Study ◽  
Paramagnetic Resonance ◽  
High Frequencies ◽  
Biologically Relevant ◽  
Lineshape Analysis ◽  
Very High Frequencies ◽  
Electron Paramagnetic ◽  
Very High

We present a fundamental study of a CW EPR lineshape analysis-based approach to determining Gd–Gd distances at very high frequencies (240 GHz). The approach is demonstrated from cryogenic to biologically-relevant temperatures.

scholarly journals Study on the Microstructure of Polyether Ether Ketone Films Irradiated with 170 keV Protons by Grazing Incidence Small Angle X-ray Scattering (GISAXS) Technology

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2717
Author(s):  
Hongxia Li ◽  
Jianqun Yang ◽  
Feng Tian ◽  
Xingji Li ◽  
Shangli Dong
Keyword(s):  
Structural Information ◽  
Absorbed Dose ◽  
Grazing Incidence ◽  
Scanning Calorimetry ◽  
Paramagnetic Resonance ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
Electron Paramagnetic

Polyether ether ketone (PEEK) films irradiated with 170 keV protons were calculated by the stopping and ranges of ions in matter (SRIM) software. The results showed that the damage caused by 170 keV protons was only several microns of the PEEK surface, and the ionization absorbed dose and displacement absorbed dose were calculated. The surface morphology and roughness of PEEK after proton irradiation were studied by atomic force microscope (AFM). GISAXS was used to analyze the surface structural information of the pristine and irradiated PEEK. The experimental results showed that near the surface of the pristine and irradiated PEEK exists a peak, and the peak gradually disappeared with the increasing of the angles of incidence and the peak changed after irradiation, which implies the 170 keV protons have an effect on PEEK structure. The influences of PEEK irradiated with protons on the melting temperature and crystallization temperature was investigated by differential scanning calorimetry (DSC). The DSC results showed that the crystallinity of the polymer after irradiation decreased. The structure and content of free radicals of pristine and irradiated PEEK were studied by Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR). The stress and strain test results showed that the yield strength of the PEEK irradiated with 5 × 1015 p/cm2 and 1 × 1016 p/cm2 was higher than the pristine, but the elongation at break of the PEEK irradiated with 5 × 1015 p/cm2 and 1 × 1016 p/cm2 decreased obviously.

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