Exploring �-sheet structures is important for developing an understanding of the formation and the structure of fibrils formed upon peptide self-aggregation. These fibrils differ in terms of thickness, length and helicity. IR and recently also vibrational circular dichroism (VCD) spectroscopy have emerged as ideal tools for characterizing cross-�-sheet structures. This paper shows that in addition isotropic and anisotropic Raman scattering can be used to discriminate between parallel and antiparallel �-sheets. We used an excitonic coupling model to model the amide I profile of IR, Raman and VCD spectra of different type of �-sheet fibrils. The results are compared with experimental data for a short alanine based peptide AAKAAY and its isotopic derivatives, which have recently been shown to self-aggregate into rather strong fibrils. Fibrilization of this peptide gives rise to a strongly enhanced amide I VCD signal, which reflects the helicity of the formed fibrils.

Modeling the amide I band profiles of IR, isotropic Raman and anisotropic Raman of b-sheet fibrils

244th National Meeting (2012)

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