Infrared Linear Dichroism Spectroscopy on Amyloid Fibrils Aligned by Molecular Combing

• Published in: Biomacromolecules Vol. 12; no. 5; pp. 1810 - 1821
• Main Authors: Rodríguez-Pérez, José C, Hamley, Ian W, Squires, Adam M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.05.2011
• Subjects: Amino Acid Sequence; Amyloid - chemistry; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Molecular biophysics; Spectrum Analysis - methods; Structure in molecular biology; X-Ray Diffraction; Dichroism; Molecular combing; Amyloid; Fibril
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm200167n

We report the use of molecular combing as an alignment method to obtain macroscopically oriented amyloid fibrils on planar surfaces. The aligned fibrils are studied by polarized infrared spectroscopy. This gives structural information that cannot be definitively obtained from standard infrared experiments on isotropic samples, for example, confirmation of the characteristic cross-β amyloid core structure, the side-chain orientation from specific amino acids, and the arrangement of the strands within the fibrils, as we demonstrate here. We employed amyloid fibrils from hen egg white lysozyme (HEWL) and from a model octapeptide. Our results demonstrate molecular combing as a straightforward method to align amyloid fibrils, producing highly anisotropic infrared linear dichroism (IRLD) spectra.