Amyloid-like aggregates of a plant protein: a case of a sweet-tasting protein, monellin

We report here a novel case of amyloid-like aggregation of a plant protein. A sweet-tasting protein, monellin, experiences an irreversible heat denaturation at pH 2.5 and 85 degrees C. Addition of 100 mM NaCl couples this process with protein aggregation. The aggregates mere structured as regular fibers with similar to 10 nm width and capable of binding to Congo red, similarly to well-known amyloid fibrils. The amyloid-like aggregation process was also successfully monitored with a calorimetric method. This work supports the universality of the amyloid-like aggregation, not restricted to some special categories of protein. (C) 1999 Federation of European Biochemical Societies.