Dresden 2014 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 41: Biomaterials and Biopolymers II (joint CPP/BP)

BP 41.1: Vortrag

Donnerstag, 3. April 2014, 15:00–15:15, ZEU 222

Observing the onset of amyloid fibril formation at interfaces with Reflection Anisotropy Spectroscopy — •Heike Arnolds, Sergio Mauri, Caroline Smith, and Peter Weightman — Surface Science Research Centre, University of Liverpool, Oxford Road, Liverpool L69 3BX, UK

The interaction of proteins with surfaces facilitates misfolding and leads to the formation of amyloid fibrils. This has a major impact on human health, because fibril formation during drug storage and injection decreases drug activity, for example in human insulin, and fibril formation at cell membranes is associated with diseases such as Alzheimer's. The key event is the formation of β-sheet structures which further self-assemble into amyloid fibrils, but there is little mechanistic understanding to date due to a dearth of experimental techniques which are sensitive and informative enough. Reflection anisotropy spectroscopy (RAS) provides structural information of adsorbates from the azimuthal angular variation of the optical spectrum about the direction of the incident light. It has been used for example to monitor the conformational change in cytochrome P450 in real time [1]. Here we apply the technique to the adsorption of human insulin on model methyl and amine terminated stepped Si(111) surfaces. By comparison to attenuated total reflection infrared spectra of the amide I band, we show that RAS can detect a helical β-sheet structure, which likely represents the onset of fibril formation.

[1]P. Weightman et al, Phys Rev E 88, 032715 (2013)