Interactions of Aggregating Peptides Probed by IR-UV Action Spectroscopy

28 November 2018, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


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.


peptide aggregation process
IR Spectroscopy
hydrogen bond networks

Supplementary materials

Electronic Supplementary Information FaradayDiscussions BakelsRijs


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.