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Spectroscopy
Volume 19 (2005), Issue 4, Pages 199-205
http://dx.doi.org/10.1155/2005/104348

Amyloid fibril formation by bovine cytochrome c

Natalia S. de Groot and Salvador Ventura

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

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Bovine heart cytochrome c is an all-a 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 a-helical protein can lead to its polymerization into ß-sheet rich structures and suggest that this process does not depend on the population of partially folded monomeric states with extensive ß-sheet structure.