Distinguishing crystal-like amyloid fibrils and glass-like amorphous aggregates from their kinetics of formation.
Proc Natl Acad Sci U S A
; 109(36): 14446-51, 2012 Sep 04.
Article
en En
| MEDLINE
| ID: mdl-22908252
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. ß(2)-microglobulin (ß2m), 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.
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1
Banco de datos:
MEDLINE
Asunto principal:
Conformación Proteica
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Microglobulina beta-2
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Pliegue de Proteína
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Deficiencias en la Proteostasis
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Amiloide
Límite:
Humans
Idioma:
En
Año:
2012
Tipo del documento:
Article