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Self‐assembly of the octapeptide lanreotide and lanreotide‐based derivatives: the role of the aromatic residues
Author(s) -
Pandit Anjali,
Fay Nicolas,
Bordes Luc,
Valéry Céline,
CherifCheikh Roland,
Robert Bruno,
Artzner Franck,
Paternostre MaÏté
Publication year - 2008
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.913
Subject(s) - lanreotide , chemistry , peptide , tryptophan , aromatic amino acids , hydrogen bond , supramolecular chemistry , fluorescence , aromaticity , salt bridge , stereochemistry , crystallography , organic chemistry , molecule , amino acid , biochemistry , crystal structure , growth hormone , physics , quantum mechanics , hormone , acromegaly , mutant , gene
We investigated the spectroscopic properties of the aromatic residues in a set of octapeptides with various self‐assembly properties. These octapeptides are based on lanreotide, a cyclic peptide analogue of somatostatin‐14 that spontaneously self‐assembles into very long and monodisperse hollow nanotubes. A previous study on these lanreotide‐based derivatives has shown that the disulfide bridge, the peptide hairpin conformation and the aromatic residues are involved in the self‐assembly process and that modification of these properties either decreases the self‐assembly propensity or modifies the molecular packing resulting in different self‐assembled architectures. In this study we probed the local environment of the aromatic residues, naphthyl‐alanine, tryptophan and tyrosine, by Raman and fluorescence spectroscopy, comparing nonassembled peptides at low concentrations with the self‐assembled ones at high concentrations. As expected, the spectroscopic characteristics of the aromatic residues were found to be sensitive to the peptide–peptide interactions. Among the most remarkable features we could record a very unusual Raman spectrum for the tyrosine of lanreotide in relation to its propensity to form H‐bonds within the assemblies. In Lanreotide nanotubes, and also in the supramolecular architectures formed by its derivatives, the tryptophan side chain is water‐exposed. Finally, the low fluorescence polarization of the peptide aggregates suggests that fluorescence energy transfer occurs within the nanotubes. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.