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Updated: Jul 26, 2026

05:48
Rapid Generation of Amyloid from Native Proteins In vitro
Published on: December 5, 2013
Molecular basis for amyloid fibril formation and stability
O Sumner Makin1, Edward Atkins, Pawel Sikorski
1Structural Medicine, Department of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Hills Road, Cambridge CB2 2XY, United Kingdom.
Summary
Researchers determined the detailed molecular structure of amyloid fibrils using sequence-designed polypeptides. This breakthrough reveals antiparallel beta-sheet arrangements and stabilizing interactions within amyloid fibers.
Area of Science:
- Structural Biology
- Biochemistry
- Molecular Medicine
Background:
- The precise molecular structure of amyloid fibrils has been difficult to ascertain due to challenges in crystallizing these structures.
- Amyloid fibrils are associated with various neurodegenerative diseases, making their structural elucidation critical for understanding disease mechanisms.
Purpose of the Study:
- To determine the high-resolution molecular structure of amyloid fibrils.
- To elucidate the specific arrangement of polypeptides and stabilizing interactions within amyloid fibers.
Main Methods:
- Crystallization of amyloid fibers using a sequence-designed polypeptide.
- High-resolution X-ray and electron diffraction analysis (1 Å resolution).
Main Results:
- Detailed molecular structure of amyloid fibers determined.
- Polypeptides form fibrous crystals with an antiparallel beta-sheet, cross-beta arrangement.
- Identified pi-bonding between phenylalanine rings and salt-bridges (glutamic acid-lysine) as key stabilizing interactions.
Conclusions:
- The study provides unprecedented insight into the molecular architecture of amyloid fibrils.
- Identified stabilizing interactions (pi-bonding and salt-bridges) are crucial for amyloid fiber formation and stability.
- Findings may inform therapeutic strategies targeting amyloid-related diseases.
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Protein Folding
Overview
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Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
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A protein's shape is critical to its function. For example, an enzyme can...
Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Oligosaccharide Assembly
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
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Protein Folding
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
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Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...

