Alzheimer’s disease, Parkinson’s disease, type-II diabetes, and prion diseases like BSE all involve the deposition of amyloid fibrils in tissues and organs. These are fibrous clumps of incorrectly folded proteins; their exact structures and their roles in pathological processes are not yet completely understood.
By using electron microscopic images of flash frozen samples, researchers have now been able to examine the exact structure of Alzheimer’s amyloid fibrils and to assess their mechanical properties. As the team reports in the journal Angewandte Chemie, the fibrils are very stiff—one of the underlying causes of their pathogenicity.
Because amyloid fibrils are very difficult to analyze with traditional biophysical techniques, Marcus Fändrich (Max Planck Unit for Enzymology of Protein Folding, Halle/Saale, Germany), Carsten Sachse (MRC Laboratory of Molecular Biology, Cambridge, UK), and Nikolaus Grigorieff (Brandeis University, Waltham, USA) were forced to take another approach: They examined Alzheimer’s amyloid fibrils by electron cryomicroscopy. “These experiments allowed us to examine the structure of the fibrils at a previously unattainable resolution,” explains Fändrich.
The fibrils appear in twisted bands about 20 nm wide and are often bent in the raw electron microscopic images. “These bent fibrils are a snapshot of the fibrils in solution,” says Fändrich. “We use the degree of bending and twisting to calculate how stiff the fibrils are.” This revealed that the Alzheimer’s amyloid fibrils are relatively rigid structures. “The uncontrolled formation of such stiff fibrils is presumably critical for the pathogenicity of amyloid fibrils,” reports Fändrich. “In many amyloid diseases, the fibrils are preferentially deposited in tissues that are normally contractile or elastic, like the heart muscle or the walls of blood vessels. Medical findings indicate that the fibrils somewhat stiffen these tissues.”
“In addition, our data may help to better evaluate the possible uses of amyloid fibers as novel biotechnological agents,” reports Fändrich. Based on their material properties and ease of modification, amyloid fibers are potentially interesting as novel building materials.
Author: Marcus Fändrich, Max Planck Research Unit for Enzymology of Protein Folding, Halle (Germany), http://www.enzyme-halle.mpg.de/amyloid/staff.htm
Title: Nanoscale Flexibility Parameters of Alzheimer Amyloid Fibrils Determined by Electron Cryo-Microscopy
Angewandte Chemie International Edition 2010, 49, No. 7, Permalink: http://dx.doi.org/10.1002/anie.200904781
Study identifies RNA molecule that shields breast cancer stem cells from immune system
23.05.2017 | Princeton University
“Pregnant” Housefly Males Demonstrate the Evolution of Sex Determination
23.05.2017 | Universität Zürich
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Earth Sciences
23.05.2017 | Life Sciences
23.05.2017 | Physics and Astronomy