In vitro formation of amyloid from α-synuclein is dominated by reactions at hydrophobic interfaces

Jeremy Pronchik, Xianglan He, Jason T. Giurleo, David Talaga

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Abstract

Most in vitro investigations of α-Synuclein (αSyn) aggregation and amyloidogenesis use agitation in the presence of air and/or Teflon to accelerate kinetics. The effect of the agitation is implicitly or explicitly attributed to mass transfer or fibril fragmentation. This paper evaluates these hypotheses by agitating αSyn under typical amyloidogenic conditions with controlled numbers of balls made of polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA), and borosilicate glass with no headspace. Amyloid was assayed using thioflavin T fluorescence and atomic force microscopy. The observed kinetics were proportional to the PTFE surface area; the effects of PMMA and glass balls were negligible by comparison. No amyloid was observed to form in the absence of mixing balls. Agitation with only air also showed accelerated kinetics but different aggregate morphology. The results indicate that the mechanism active in agitation experiments is dominated by reactions at the hydrophobic-water interface. Of the mass transfer, fragmentation, and hydrophobic interface hypotheses, only the last is capable of explaining the data. Condition and sequence determinants of amyloidogenic propensity that have thus far been reported must be reinterpreted as being reflective of partitioning to hydrophobic-water interfaces. Comparable hydrophobic interfaces are not found in vivo.

Original languageEnglish
Pages (from-to)9797-9803
Number of pages7
JournalJournal of the American Chemical Society
Volume132
Issue number28
DOIs
StatePublished - 21 Jul 2010

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Synucleins
Polytetrafluoroethylene
Polytetrafluoroethylenes
Amyloid
Polymethyl Methacrylate
Kinetics
Glass
Mass transfer
Air
Borosilicate glass
Water
Atomic Force Microscopy
Atomic force microscopy
Agglomeration
Fluorescence
In Vitro Techniques
Experiments

Cite this

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title = "In vitro formation of amyloid from α-synuclein is dominated by reactions at hydrophobic interfaces",
abstract = "Most in vitro investigations of α-Synuclein (αSyn) aggregation and amyloidogenesis use agitation in the presence of air and/or Teflon to accelerate kinetics. The effect of the agitation is implicitly or explicitly attributed to mass transfer or fibril fragmentation. This paper evaluates these hypotheses by agitating αSyn under typical amyloidogenic conditions with controlled numbers of balls made of polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA), and borosilicate glass with no headspace. Amyloid was assayed using thioflavin T fluorescence and atomic force microscopy. The observed kinetics were proportional to the PTFE surface area; the effects of PMMA and glass balls were negligible by comparison. No amyloid was observed to form in the absence of mixing balls. Agitation with only air also showed accelerated kinetics but different aggregate morphology. The results indicate that the mechanism active in agitation experiments is dominated by reactions at the hydrophobic-water interface. Of the mass transfer, fragmentation, and hydrophobic interface hypotheses, only the last is capable of explaining the data. Condition and sequence determinants of amyloidogenic propensity that have thus far been reported must be reinterpreted as being reflective of partitioning to hydrophobic-water interfaces. Comparable hydrophobic interfaces are not found in vivo.",
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In vitro formation of amyloid from α-synuclein is dominated by reactions at hydrophobic interfaces. / Pronchik, Jeremy; He, Xianglan; Giurleo, Jason T.; Talaga, David.

In: Journal of the American Chemical Society, Vol. 132, No. 28, 21.07.2010, p. 9797-9803.

Research output: Contribution to journalArticleResearchpeer-review

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