1. Distinguishing crystal-like amyloid fibrils and glass-like amorphous aggregates from their kinetics of formation.
- Author
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Yuichi Yoshimura, Yuxi Lin, Hisashi Yagi, Young-Ho Lee, Kitayama, Hiroki, Sakurai, Kazumasa, Masatomo So, Ogi, Hirotsugu, Naiki, Hironobu, and Goto, Yuji
- Subjects
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AMYLOID beta-protein , *GLASS transition temperature , *PROTEIN folding , *MICROGLOBULINS , *LIGHT scattering , *CRYSTALLIZATION - Abstract
Amyloid fibrils and amorphous aggregates are two types of aberrant aggregates associated with protein misfolding diseases. Although they differ in morphology, the two forms are often treated indiscriminately, β2-microglobulin (β2m), a protein responsible for dialysis-related amyloidosis, forms amyloid fibrils or amorphous aggregates depending on the NaCl concentration at pH 2.5. We compared the kinetics of their formation, which was monitored by measuring thioflavin T fluorescence, light scattering, and 8-anilino-1-naphthalenesulfonate fluorescence. Thioflavin T fluorescence specifically monitors amyloid fibrillation, whereas light scattering and 8-anilino-1-naphthalenesulfonate fluorescence monitor both amyloid fibrillation and amorphous aggregation. The amyloid fibrils formed via a nucleation-dependent mechanism in a supersaturated solution, analogous to crystallization. The lag phase of fibrillation was reduced upon agitation with stirring or ultrasonic irradiation, and disappeared by seeding with preformed fibrils. In contrast, the glass-like amorphous aggregates formed rapidly without a lag phase. Neither agitation nor seeding accelerated the amorphous aggregation. Thus, by monitoring the kinetics, we can distinguish between crystal-like amyloid fibrils and glass-like amorphous aggregates. Solubility and supersaturation will be key factors for further understanding the aberrant aggregation of proteins. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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