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| 2. |
- Popp, David, et al.
(författare)
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Flow-aligned, single-shot fiber diffraction using a femtosecond X-ray free-electron laser
- 2017
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Ingår i: CYTOSKELETON. - : WILEY. - 1949-3584 .- 1949-3592. ; 74:12, s. 472-481
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Tidskriftsartikel (refereegranskat)abstract
- A major goal for X-ray free-electron laser (XFEL) based science is to elucidate structures of biological molecules without the need for crystals. Filament systems may provide some of the first single macromolecular structures elucidated by XFEL radiation, since they contain one-dimensional translational symmetry and thereby occupy the diffraction intensity region between the extremes of crystals and single molecules. Here, we demonstrate flow alignment of as few as 100 filaments (Escherichia coli pili, F-actin, and amyloid fibrils), which when intersected by femtosecond X-ray pulses result in diffraction patterns similar to those obtained from classical fiber diffraction studies. We also determine that F-actin can be flow-aligned to a disorientation of approximately 5 degrees. Using this XFEL-based technique, we determine that gelsolin amyloids are comprised of stacked -strands running perpendicular to the filament axis, and that a range of order from fibrillar to crystalline is discernable for individual -synuclein amyloids.
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| 3. |
- Maji, Samir K, et al.
(författare)
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Functional Amyloids As Natural Storage of Peptide Hormones in Pituitary Secretory Granules
- 2009
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Ingår i: SCIENCE. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5938, s. 328-332
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Tidskriftsartikel (refereegranskat)abstract
- Amyloids are highly organized cross-beta-sheet-rich protein or peptide aggregates that are associated with pathological conditions including Alzheimers disease and type II diabetes. However, amyloids may also have a normal biological function, as demonstrated by fungal prions, which are involved in prion replication, and the amyloid protein Pmel17, which is involved in mammalian skin pigmentation. We found that peptide and protein hormones in secretory granules of the endocrine system are stored in an amyloid-like cross-beta-sheet-rich conformation. Thus, functional amyloids in the pituitary and other organs can contribute to normal cell and tissue physiology.
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| 4. |
- Benson, Merrill D., et al.
(författare)
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Amyloid nomenclature 2018 : recommendations by the International Society of Amyloidosis (ISA) nomenclature committee
- 2018
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Ingår i: Amyloid. - : Informa UK Limited. - 1350-6129 .- 1744-2818. ; 25:4, s. 215-219
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Tidskriftsartikel (refereegranskat)abstract
- The nomenclature committee of the International Society of Amyloidosis (ISA) meets every second year to discuss and formulate recommendations. The conclusions from the discussion at the XVI International Symposium on Amyloidosis in Kumamoto, Japan, 25–29 March 2018 and afterwards are summarized in this Nomenclature Article. From having recommended the use of the designation “amyloid fibril” for in vivo material only, ISA’s nomenclature committee now accepts its use more broadly following the international scientific literature. However, it is important always to stress the origin of the β-fibrils in order to avoid misunderstanding. Given the more broad use of the word “amyloid” several classes of amyloid fibrils may be distinguished. For the medical in vivo situation, and to be included in the amyloid nomenclature list, “amyloid” still means mainly extracellular tissue deposits of protein fibrils, recognized by specific properties, such as green-yellow birefringence after staining with Congo red. It should also be underlined that in vivo amyloid fibrils, in addition to the main protein contain associated compounds, particularly serum amyloid P-component (SAP) and proteoglycans, mainly heparan sulfate proteoglycan. With this definition there are presently 36 human amyloid proteins of which 14 appear only associated with systemic amyloidosis and 19 as localized forms. Three proteins can occur both as localized and systemic amyloidosis. Strictly intracellular aggregates are not included in this list.
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| 5. |
- Benson, Merrill D., et al.
(författare)
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Amyloid nomenclature 2020 : update and recommendations by the International Society of Amyloidosis (ISA) nomenclature committee
- 2020
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Ingår i: Amyloid. - : TAYLOR & FRANCIS LTD. - 1350-6129 .- 1744-2818. ; 27:4, s. 217-222
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Tidskriftsartikel (refereegranskat)abstract
- The ISA Nomenclature Committee met electronically before and directly after the XVII ISA International Symposium on Amyloidosis, which, unfortunately, had to be virtual in September 2020 due to the ongoing COVID-19 pandemic instead of a planned meeting in Tarragona in March. In addition to confirmation of basic nomenclature, several additional concepts were discussed, which are used in scientific amyloid literature. Among such concepts are cytotoxic oligomers, protofibrils, primary and secondary nucleation, seeding and cross-seeding, amyloid signature proteins, and amyloid plaques. Recommendations for their use are given. Definitions of amyloid and amyloidosis are confirmed. Possible novel human amyloid fibril proteins, appearing as 'classical' in vivo amyloid, were discussed. It was decided to include fibulin-like extracellular matrix protein 1 (amyloid protein: AEFEMP1), which appears as localised amyloid in portal veins. There are several possible amyloid proteins under investigation, and these are included in a new Table.
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| 6. |
- Buxbaum, Joel N., et al.
(författare)
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Amyloid nomenclature 2022 : update, novel proteins, and recommendations by the International Society of Amyloidosis (ISA) Nomenclature Committee
- 2022
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Ingår i: Amyloid. - : Taylor & Francis Group. - 1350-6129 .- 1744-2818. ; 29:4, s. 213-219
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Tidskriftsartikel (refereegranskat)abstract
- The Nomenclature Committee of the International Society of Amyloidosis met at the XVIII International Symposium on Amyloidosis in September and virtually in October 2022 with discussions resulting in this upgraded nomenclature recommendation. The nomenclature principles remain unchanged but there is an ongoing discussion regarding the importance and varying nature of intracellular protein aggregates, particularly those associated with neurodegenerative diseases. Six novel proteins were added to the list of human amyloid fibril proteins. Of these, three are polypeptide hormones and two currently utilised peptide drugs, making the number of known iatrogenic amyloid forms four, all appearing as subcutaneous nodules at the injection site. The sixth novel amyloid fibril protein is the transmembrane 106B protein, forming intracellular amyloid fibrils in disorders associated with frontotemporal dementia. The number of known human amyloid fibril proteins is now 42.
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| 7. |
- Krotee, Pascal, et al.
(författare)
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Atomic structures of fibrillar segments of hIAPP suggest tightly mated beta-sheets are important or cytotoxicity
- 2017
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Ingår i: eLIFE. - 2050-084X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- hIAPP fibrils are associated with Type-II Diabetes, but the link of hIAPP structure to islet cell death remains elusive. Here we observe that hIAPP fibrils are cytotoxic to cultured pancreatic beta-cells, leading us to determine the structure and cytotoxicity of protein segments composing the amyloid spine of hIAPP. Using the cryoEM method MicroED, we discover that one segment, 19-29 S20G, forms pairs of beta-sheets mated by a dry interface that share structural features with and are similarly cytotoxic to full-length hIAPP fibrils. In contrast, a second segment, 15-25 WT, forms non-toxic labile beta-sheets. These segments possess different structures and cytotoxic effects, however, both can seed full-length hIAPP, and cause hIAPP to take on the cytotoxic and structural features of that segment. These results suggest that protein segment structures represent polymorphs of their parent protein and that segment 19-29 S20G may serve as a model for the toxic spine of hIAPP.
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