Assessing the Utility of Infrared Spectroscopy as a Structural Diagnostic Tool for beta-Sheets in Self-Assembling Aromatic Peptide Amphiphiles

Scott Fleming, Pim W. J. M. Frederix, Ivan Ramos Sasselli, Neil T. Hunt, Rein V. Ulijn*, Tell Tuttle

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

123 Citaten (Scopus)


beta-Sheets are a commonly found structural motif in self-assembling aromatic peptide amphiphiles, and their characteristic "amide I" infrared (IR) absorption bands are routinely used to support the formation of supramolecular structure. In this paper, we assess the utility of IR spectroscopy as a structural diagnostic tool for this class of self-assembling systems. Using 9-fluorene-methyloxycarbonyl dialanine (Fmoc-AA) and the analogous 9-fluorene-methylcarbonyl dialanine (Fmc-AA) as examples, we show that the origin of the band around 1680-1695 cm(-1) in Fourier transform infrared (FTIR) spectra, which was previously assigned to an antiparallel beta-sheet conformation, is in fact absorption of the stacked carbamate group in Fmoc-peptides. IR spectra from C-13-labeled samples support our conclusions. In addition, DFT frequency calculations on small stacks of aromatic peptides help to rationalize these results in terms of the individual vibrational modes.

Originele taal-2English
Pagina's (van-tot)9510-9515
Aantal pagina's6
Nummer van het tijdschrift30
StatusPublished - 30-jul.-2013
Extern gepubliceerdJa

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