Amyloid fibril formation by bovine cytochrome c

Article type: Research Article

Authors: de Groot, Natalia S. | Ventura, Salvador

Affiliations: Departament de Bioquimica i Biologia Molecular, Universitat Autonoma de Barcelona and Institut de Biotecnologia i de Biomedicina, 08193 Bellaterra (Barcelona), Spain

Note: [] Corresponding author. Tel.: +34 93 581 41 47; Fax: +34 93 581 12 64; E-mail: salvador.ventura@uab.es.

Abstract: Bovine heart cytochrome c is an all-α globular protein containing a covalently bound heme group. Prolonged incubation at 75°C in mild alkaline solution damages the prosthetic group and results in permanent unfolding of the polypeptide chain. Under this conditions, cytochrome c aggregates into fibrillar structures. Characterization by transmission electron microscopy and thioflavin-T binding assays shows that these species posses the characteristics of fibrils associated with the family of amyloid diseases. Our findings indicate that destabilization of the native fold of this highly α-helical protein can lead to its polymerization into β-sheet rich structures and suggest that this process does not depend on the population of partially folded monomeric states with extensive β-sheet structure.

Keywords: Amyloid formation, cytochrome c, protein misfolding, protein denaturation, helical proteins

Journal: Spectroscopy, vol. 19, no. 4, pp. 199-205, 2005