Amyloid fibrils formation and amorphous aggregation in concanavalin A - Analytical Methods & Tools for Lyophilization

Amyloid fibrils formation and amorphous aggregation in concanavalin A
Received 7 July 2006; accepted 25 July 2006. Available online 2 August 2006.
Valeria Vetria, c, Claudio Canaleb, Annalisa Relinib, Fabio Librizzia, , , Valeria Militelloa, c, Alessandra Gliozzib and Maurizio Leonea, c
Biophysical Chemistry
Volume 125, Issue 1 , January 2007
ScienceDirect
Copyright ? 2006 Elsevier B.V. All rights reserved.
aUniversit? di Palermo, Dipartimento di Scienze Fisiche ed Astronomiche, Via Archirafi 36, 90123 Palermo, Italy
bUniversit? di Genova, Dipartimento di Fisica, Via Dodecaneso 33, 16146 Genova, Italy
cConsiglio Nazionale delle Ricerche, Istituto di Biofisica, Sez. di Palermo, Via U. La Malfa 153, 90146 Palermo, Italy
Abstract
We here report an experimental study on the thermal aggregation process of concanavalin A, a protein belonging to the legume lectins family.
The aggregation process and the involved conformational changes of the protein molecules were followed by means of fluorescence techniques, light scattering, circular dichroism, zeta potential measurements and atomic force microscopy. Our results show that the aggregation process of concanavalin A may evolve through two distinct pathways leading, respectively, to the formation of amyloids or amorphous aggregates. The relative extent of the two pathways is determined by pH, as amyloid aggregation is favored at high pH values ( 9), while the formation of amorphous aggregates is favored at low pH ( 5). At difference from amorphous aggregation, the formation of amyloid fibrils requires significant conformational changes on the protein, both at secondary and tertiary structural level. To our knowledge, this is the first observation of amyloid fibrils from concanavalin A.
Keywords: Concanavalin A; Protein aggregation; Amyloids; Thioflavin T fluorescence; Atomic force microscopy; Circular dichroism

You can view the abstract online. A subscription is required to view the full text or it can be purchased online.