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Interactions of Aggregating Peptides Probed by IR-UV Action Spectroscopy

preprint
submitted on 28.11.2018, 09:32 and posted on 28.11.2018, 15:55 by Sjors Bakels, E.M. Meijer, Mart Greuell, Sebastiaan Porskamp, George Rouwhorst, Jerome Mahe, Marie-Pierre Gaigeot, Anouk Rijs
Peptide aggregation, the self-assembly of peptides into structured beta-sheet fibril structures, is driven by a combination of intra- and intermolecular interactions. Here, the interplay between intramolecular and formed inter-sheet hydrogen bonds and the effect of dispersion interactions on the formation of neutral, isolated, peptide dimers is studied by infrared action spectroscopy. Therefore, four different homo- and hetereogeneous dimers formed from three different alanine-based model peptides have been studied under controlled and isolated conditions. The peptides differ from one another in the presence and location of a UV chromophore containing cap on either the C- or N-terminus. Conformations of the monomers of the peptides direct the final dimer structure: strongly hydrogen bonded or folded structures result in weakly bound dimers. Here the intramolecular hydrogen bonds are favored over new intermolecular hydrogen bond interactions. In contrast, linearly folded monomers are the ideal template to form parallel beta-sheet type structures. The weak intramolecular hydrogen bonds present in the linear monomers are replaced by the stronger inter-sheet hydrogen bond interactions. The influence of π-π disperion interactions on the structure of the dimer is minimal, the phenyl rings have the tendency to fold away from the peptide backbone to favour intermolecular hydrogen bond interactions. Quantum chemical calculations confirm our experimental observations.

Funding

NWO Rekentijd contract 16327

History

Email Address of Submitting Author

a.rijs@science.ru.nl

Institution

Radboud University, FELIX Laboratory

Country

The Netherlands

ORCID For Submitting Author

0000-0002-7446-9907

Declaration of Conflict of Interest

no conflict of interest

Version Notes

version1 (submitted for review)

Exports