Mechanical Stress Affects Glucagon Fibrillation Kinetics and Fibril Structure

详细信息    查看全文

• 作者：Francesca Macchi ; S酶ren V. Hoffmann ; Martin Carlsen ; Brian Vad ; Alberto Imparato ; Christian Rischel ; Daniel E. Otzen
• 刊名：Langmuir
• 出版年：2011
• 出版时间：October 18, 2011
• 年：2011
• 卷：27
• 期：20
• 页码：12539-12549
• 全文大小：1088K
• 年卷期：v.27,no.20(October 18, 2011)
• ISSN：1520-5827

文摘

Mechanical stress can strongly influence the capability of a protein to aggregate and the kinetics of aggregation, but there is little insight into the underlying mechanism. Here we study the effect of different mechanical stress conditions on the fibrillation of the peptide hormone glucagon, which forms different fibrils depending on temperature, pH, ionic strength, and concentration. A combination of spectroscopic and microscopic data shows that fibrillar polymorphism can also be induced by mechanical stress. We observed two classes of fibrils: a low-stress and a high-stress class, which differ in their kinetic profiles, secondary structure as well as morphology and that are able to self-propagate in a template-dependent fashion. The bending rigidity of the low-stress fibrils is sensitive to the degree of mechanical perturbation. We propose a fibrillation model, where interfaces play a fundamental role in the switch between the two fibrillar classes. Our work also raises the cautionary note that mechanical perturbation is a potential source of variability in the study of fibrillation mechanisms and fibril structures.