| 1. |
- Dhulesia, Anne, et al.
(författare)
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Local Cooperativity in an Amyloidogenic State of Human Lysozyme Observed at Atomic Resolution.
- 2010
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 132:44, s. 15580-15588
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Tidskriftsartikel (refereegranskat)abstract
- The partial unfolding of human lysozyme underlies its conversion from the soluble state into amyloid fibrils observed in a fatal hereditary form of systemic amyloidosis. To understand the molecular origins of the disease, it is critical to characterize the structural and physicochemical properties of the amyloidogenic states of the protein. Here we provide a high-resolution view of the unfolding process at low pH for three different lysozyme variants, the wild-type protein and the mutants I56T and I59T, which show variable stabilities and propensities to aggregate in vitro. Using a range of biophysical techniques that includes differential scanning calorimetry and nuclear magnetic resonance spectroscopy, we demonstrate that thermal unfolding under amyloidogenic solution conditions involves a cooperative loss of native tertiary structure, followed by progressive unfolding of a compact, molten globule-like denatured state ensemble as the temperature is increased. The width of the temperature window over which the denatured ensemble progressively unfolds correlates with the relative amyloidogenicity and stability of these variants, and the region of lysozyme that unfolds first maps to that which forms the core of the amyloid fibrils formed under similar conditions. Together, these results present a coherent picture at atomic resolution of the initial events underlying amyloid formation by a globular protein.
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| 2. |
- Horrocks, Mathew Harry, et al.
(författare)
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Single-molecule imaging of individual amyloid protein aggregates in human biofluids.
- 2016
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Ingår i: ACS chemical neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 16;7:3, s. 399-406
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Tidskriftsartikel (refereegranskat)abstract
- The misfolding and aggregation of proteins into amyloid fibrils characterizes many neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. We report here a method, termed SAVE (single aggregate visualization by enhancement) imaging, for the ultra-sensitive detection of individual amyloid fibrils and oligomers using single-molecule fluorescence microscopy. We demonstrate that this method is able to detect the presence of amyloid aggregates of alpha-synuclein, tau and amyloid-β. In addition, we show that aggregates can also be identified in human cerebrospinal fluid (CSF). Significantly, we see a two-fold increase in the average aggregate concentration in CSF from PD patients compared to age-matched controls. Taken together, we conclude that this method provides an opportunity to characterize the structural nature of amyloid aggregates in a key biofluid, and therefore has the potential to study disease progression in both animal models and humans to enhance our understanding of neurodegenerative disorders.
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