Structure of anchorless RML prion reveals motif variation between strains

2021 ◽  
Author(s):  
Forrest Hoyt ◽  
Heidi G. Standke ◽  
Efrosini Artikis ◽  
Cindi L. Schwartz ◽  
Bryan Hansen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Basis ◽  
Structural Motifs ◽  
Prion Strain ◽  
Cryo Electron Microscopy ◽  
Prion Strains ◽  
Scrapie Strain ◽  
Strain Determination ◽  
Β Sheet

Little is known about the structural basis of prion strains. Here we provide a high (3.0 Å) resolution cryo-electron microscopy-based structure of brain-derived fibrils of the mouse anchorless RML scrapie strain which, like the recently determined hamster 263K strain, has a parallel in-register β-sheet-based core. However, detailed comparisons reveal that variations in shared structural motifs provide a basis for prion strain determination.

scholarly journals Mechanisms of Strain Diversity of Disease-Associated in-Register Parallel β-Sheet Amyloids and Implications About Prion Strains

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 110 ◽  
Author(s):  
Yuzuru Taguchi ◽  
Hiroki Otaki ◽  
Noriyuki Nishida
Keyword(s):  
Electron Microscopy ◽  
Resonance Spectroscopy ◽  
Post Translational Modifications ◽  
Prion Strain ◽  
Local Structures ◽  
Strain Diversity ◽  
Cryo Electron Microscopy ◽  
Prion Strains ◽  
Dynamics Simulations ◽  
Β Sheet

The mechanism of prion strain diversity remains unsolved. Investigation of inheritance and diversification of protein-based pathogenic information demands the identification of the detailed structures of abnormal isoforms of the prion protein (PrPSc); however, achieving purification is difficult without affecting infectivity. Similar prion-like properties are recognized also in other disease-associated in-register parallel β-sheet amyloids including Tau and α-synuclein (αSyn) amyloids. Investigations into structures of those amyloids via solid-state nuclear magnetic resonance spectroscopy and cryo-electron microscopy recently made remarkable advances due to their relatively small sizes and lack of post-translational modifications. Herein, we review advances regarding pathogenic amyloids, particularly Tau and αSyn, and discuss implications about strain diversity mechanisms of prion/PrPSc from the perspective that PrPSc is an in-register parallel β-sheet amyloid. Additionally, we present our recent data of molecular dynamics simulations of αSyn amyloid, which suggest significance of compatibility between β-sheet propensities of the substrate and local structures of the template for stability of amyloid structures. Detailed structures of αSyn and Tau amyloids are excellent models of pathogenic amyloids, including PrPSc, to elucidate strain diversity and pathogenic mechanisms.

scholarly journals Mechanisms of strain diversity of disease-associated in-register parallel β-sheet amyloids and implications about prion strains

2018 ◽  
Author(s):  
Yuzuru Taguchi ◽  
Hiroki Otaki ◽  
Noriyuki Nishida
Keyword(s):  
Electron Microscopy ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Post Translational Modifications ◽  
Local Structures ◽  
Strain Diversity ◽  
Cryo Electron Microscopy ◽  
Prion Strains ◽  
Dynamics Simulations ◽  
Β Sheet

AbstractThe mechanism of strain diversity of prions still remains unsolved, because the investigation of inheritance and diversification of the protein-based pathogenic information demands identification of the detailed structures of abnormal isoform of prion protein (PrPSc), while it is difficult to purify for analysis without affecting the infectious nature. On the other hand, the similar prion-like properties are recognized also in other disease-associated in-register parallel β-sheet amyloids including Tau and α-synuclein (αSyn) amyloids. Investigations into structures of those amyloids by solid-state nuclear magnetic resonance spectroscopy and cryo-electron microscopy recently made remarkable advances, because of their relatively small sizes and lack of post-translational modifications. We review the advances on those pathogenic amyloids, particularly Tau and αSyn, and discuss their implications about strain diversity mechanisms of prion/PrPSc from the viewpoint that PrPSc is an in-register parallel β-sheet amyloid. We also present our recent data of molecular dynamics simulations of αSyn amyloid, which suggest significance of compatibility between β-sheet propensities of the substrate and local structures of the template for stability of the amyloid structures. Detailed structures of the αSyn and Tau amyloids are good surrogate models of pathogenic amyloids including PrPSc to elucidate not only the strain diversity but also their pathogenic mechanisms.

scholarly journals Cryo-EM structure and polymorphism of Aβ amyloid fibrils purified from Alzheimer’s brain tissue

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Marius Kollmer ◽  
William Close ◽  
Leonie Funk ◽  
Jay Rasmussen ◽  
Aref Bsoul ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Brain Tissue ◽  
Amyloid Fibrils ◽  
Structural Basis ◽  
Amyloid Angiopathy ◽  
Cryo Electron Microscopy ◽  
Aβ Amyloid ◽  
Cerebral Amyloid ◽  
Aβ Fibrils

Abstract The formation of Aβ amyloid fibrils is a neuropathological hallmark of Alzheimer’s disease and cerebral amyloid angiopathy. However, the structure of Aβ amyloid fibrils from brain tissue is poorly understood. Here we report the purification of Aβ amyloid fibrils from meningeal Alzheimer’s brain tissue and their structural analysis with cryo-electron microscopy. We show that these fibrils are polymorphic but consist of similarly structured protofilaments. Brain derived Aβ amyloid fibrils are right-hand twisted and their peptide fold differs sharply from previously analyzed Aβ fibrils that were formed in vitro. These data underscore the importance to use patient-derived amyloid fibrils when investigating the structural basis of the disease.

How Good Can Single-Particle Cryo-EM Become? What Remains Before It Approaches Its Physical Limits?

2019 ◽  
Vol 48 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Robert M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Single Particle ◽  
Energy Use ◽  
Optimal Choice ◽  
Structural Basis ◽  
Detective Quantum Efficiency ◽  
Quantum Metrology ◽  
Cryo Electron Microscopy ◽  
Induced Motion

Impressive though the achievements of single-particle cryo–electron microscopy are today, a substantial gap still remains between what is currently accomplished and what is theoretically possible. As is reviewed here, twofold or more improvements are possible as regards ( a) the detective quantum efficiency of cameras at high resolution, ( b) converting phase modulations to intensity modulations in the image, and ( c) recovering the full amount of high-resolution signal in the presence of beam-induced motion of the specimen. In addition, potential for improvement is reviewed for other topics such as optimal choice of electron energy, use of aberration correctors, and quantum metrology. With the help of such improvements, it does not seem to be too much to imagine that determining the structural basis for every aspect of catalytic control, signaling, and regulation, in any type of cell of interest, could easily be accelerated fivefold or more.

scholarly journals Structural basis of actin filament capping at the barbed-end: a cryo-electron microscopy study

2006 ◽  
Vol 25 (23) ◽  
pp. 5626-5633 ◽  
Author(s):  
Akihiro Narita ◽  
Shuichi Takeda ◽  
Atsuko Yamashita ◽  
Yuichiro Maéda
Keyword(s):  
Electron Microscopy ◽  
Actin Filament ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Structural Basis ◽  
Cryo Electron Microscopy

scholarly journals Elucidation of AMPA receptor–stargazin complexes by cryo–electron microscopy

Science ◽  
2016 ◽  
Vol 353 (6294) ◽  
pp. 83-86 ◽  
Author(s):  
Edward C. Twomey ◽  
Maria V. Yelshanskaya ◽  
Robert A. Grassucci ◽  
Joachim Frank ◽  
Alexander I. Sobolevsky
Keyword(s):  
Electron Microscopy ◽  
Cognitive Processes ◽  
Electrostatic Interactions ◽  
Structural Basis ◽  
Cryo Electron Microscopy ◽  
Activated State ◽  
Ampar Trafficking ◽  
Excitatory Neurotransmission ◽  
Binding Interfaces ◽  
The Brain

AMPA-subtype ionotropic glutamate receptors (AMPARs) mediate fast excitatory neurotransmission and contribute to high cognitive processes such as learning and memory. In the brain, AMPAR trafficking, gating, and pharmacology is tightly controlled by transmembrane AMPAR regulatory proteins (TARPs). Here, we used cryo–electron microscopy to elucidate the structural basis of AMPAR regulation by one of these auxiliary proteins, TARP γ2, or stargazin (STZ). Our structures illuminate the variable interaction stoichiometry of the AMPAR-TARP complex, with one or two TARP molecules binding one tetrameric AMPAR. Analysis of the AMPAR-STZ binding interfaces suggests that electrostatic interactions between the extracellular domains of AMPAR and STZ play an important role in modulating AMPAR function through contact surfaces that are conserved across AMPARs and TARPs. We propose a model explaining how TARPs stabilize the activated state of AMPARs and how the interactions between AMPARs and their auxiliary proteins control fast excitatory synaptic transmission.

scholarly journals Cryo-EM Reveals the Structural Basis of Microtubule Depolymerization by Kinesin-13s

2017 ◽  
Author(s):  
Matthieu P. M. H. Benoit ◽  
Ana B. Asenjo ◽  
Hernando Sosa
Keyword(s):  
Electron Microscopy ◽  
Conformational Changes ◽  
Distinct Group ◽  
Atomic Resolution ◽  
Structural Basis ◽  
Structural Elements ◽  
Microtubule Depolymerization ◽  
Cryo Electron Microscopy ◽  
Kinesin Superfamily ◽  
Motile Activity

SummaryKinesin-13s constitute a distinct group within the kinesin superfamily of motor proteins that promotes microtubule depolymerization and lacks motile activity. The molecular mechanism by which the kinesins depolymerize microtubules and are adapted to perform a seemingly very different activity from other kinesins is still unclear. To address this issue we obtained near atomic resolution cryo-electron microscopy (cryo-EM) structures of Drosophila melanogaster kinesin-13 KLP10A constructs bound to curved or straight tubulin in different nucleotide states. The structures show how nucleotide induced conformational changes near the catalytic site are coupled with kinesin-13-specific structural elements to induce tubulin curvature leading to microtubule depolymerization. The data highlight a modular structure that allows similar kinesin core motor-domains to be used for different functions, such as motility or microtubule depolymerization.

scholarly journals Molecular basis for the ATPase-powered substrate translocation by the Lon AAA+ protease

2020 ◽  
Author(s):  
Kaiming Zhang ◽  
Shanshan Li ◽  
Kan-Yen Hsieh ◽  
Shih-Chieh Su ◽  
Grigore D. Pintilie ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Conformational Changes ◽  
Molecular Basis ◽  
Structural Basis ◽  
Cryo Electron Microscopy ◽  
Adenosine Triphosphatases ◽  
Translocation Mechanism ◽  
Atp Binding And Hydrolysis ◽  
Proteolytic Chamber ◽  
Specific Nucleotide

AbstractThe Lon AAA+ (adenosine triphosphatases associated with diverse cellular activities) protease (LonA) converts ATP-fuelled conformational changes into sufficient mechanical force to drive translocation of the substrate into a hexameric proteolytic chamber. To understand the structural basis for the substrate translocation process, we have determined the cryo-electron microscopy (cryo-EM) structure of Meiothermus taiwanensis LonA (MtaLonA) at 3.6 Å resolution in a substrate-engaged state. Substrate interactions are mediated by the dual pore-loops of the ATPase domains, organized in spiral staircase arrangement from four consecutive protomers in different ATP-binding and hydrolysis states; a closed AAA+ ring is nevertheless maintained by two disengaged ADP-bound protomers transiting between the lowest and highest position. The structure reveals a processive rotary translocation mechanism mediated by LonA-specific nucleotide-dependent allosteric coordination among the ATPase domains, which is induced by substrate binding.

scholarly journals Structural basis of ER-associated protein degradation mediated by the Hrd1 ubiquitin ligase complex

Science ◽  
2020 ◽  
Vol 368 (6489) ◽  
pp. eaaz2449 ◽  
Author(s):  
Xudong Wu ◽  
Marc Siggel ◽  
Sergey Ovchinnikov ◽  
Wei Mi ◽  
Vladimir Svetlov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ubiquitin Ligase ◽  
Dynamics Simulation ◽  
Structural Basis ◽  
Cryo Electron Microscopy ◽  
Ubiquitin Ligase Complex ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Simulation Results ◽  
Membrane Region

Misfolded luminal endoplasmic reticulum (ER) proteins undergo ER-associated degradation (ERAD-L): They are retrotranslocated into the cytosol, polyubiquitinated, and degraded by the proteasome. ERAD-L is mediated by the Hrd1 complex (composed of Hrd1, Hrd3, Der1, Usa1, and Yos9), but the mechanism of retrotranslocation remains mysterious. Here, we report a structure of the active Hrd1 complex, as determined by cryo–electron microscopy analysis of two subcomplexes. Hrd3 and Yos9 jointly create a luminal binding site that recognizes glycosylated substrates. Hrd1 and the rhomboid-like Der1 protein form two “half-channels” with cytosolic and luminal cavities, respectively, and lateral gates facing one another in a thinned membrane region. These structures, along with crosslinking and molecular dynamics simulation results, suggest how a polypeptide loop of an ERAD-L substrate moves through the ER membrane.

scholarly journals Structural basis of trehalose recycling by the ABC transporter LpqY-SugABC

2020 ◽  
Vol 6 (44) ◽  
pp. eabb9833
Author(s):  
Fengjiang Liu ◽  
Jingxi Liang ◽  
Bing Zhang ◽  
Yan Gao ◽  
Xiuna Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Abc Transporter ◽  
Abc Transporters ◽  
Unique Feature ◽  
Structural Basis ◽  
Human Pathogens ◽  
Gram Positive Bacteria ◽  
Cryo Electron Microscopy ◽  
Uptake Of Nutrients ◽  
Initial Mode

In bacteria, adenosine 5′-triphosphate (ATP)–binding cassette (ABC) importers are essential for the uptake of nutrients including the nonreducing disaccharide trehalose, a metabolite that is crucial for the survival and virulence of several human pathogens including Mycobacterium tuberculosis. SugABC is an ABC transporter that translocates trehalose from the periplasmic lipoprotein LpqY into the cytoplasm of mycobacteria. Here, we report four high-resolution cryo–electron microscopy structures of the mycobacterial LpqY-SugABC complex to reveal how it binds and passes trehalose through the membrane to the cytoplasm. A unique feature observed in this system is the initial mode of capture of the trehalose at the LpqY interface. Uptake is achieved by a pivotal rotation of LpqY relative to SugABC, moving from an open and accessible conformation to a clamped conformation upon trehalose binding. These findings enrich our understanding as to how ABC transporters facilitate substrate transport across the membrane in Gram-positive bacteria.

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