Supramolecular Chiral Discrimination of D-Phenylalanine Amino Acid Based on a Perylene Bisimide Derivative.

Simona Bettini,Michela Ottolini,Zois Syrgiannis,Valentina Bonfrate,Gabriele Giancane,Maurizio Prato,Ludovico Valli

doi:10.3389/fbioe.2020.00160

Abstract

The interaction between homochiral substituted perylene bisimide (PBI) molecule and the D enantiomer of phenylalanine amino acid was monitored. Spectroscopic transitions of PBI derivative in aqueous solution in the visible range were used to evaluate the presence of D-phenylalanine. UV-visible, fluorescence, FT-IR, and AFM characterizations showed that D-phenylalanine induces significant variations in the chiral perylene derivative aggregation state and the mechanism is enantioselective as a consequence of the 3D analyte structure. The interaction mechanism was further investigated in presence of interfering amino acid (D-serine and D-histidine) confirming that both chemical structure and its 3D structure play a crucial role for the amino acid discrimination. A D-phenylalanine fluorescence sensor based on perylene was proposed. A limit of detection (LOD) of 64.2 ± 0.38 nM was calculated in the range 10–7–10–5 M and of 1.53 ± 0.89 μM was obtained in the range 10–5 and 10–3 M.

Highlights

In the first half of the XIX century Louis Pasteur discovered, during his studies about the optical characteristics of a well-known chemical compound largely investigated in oenology, i.e., the tartaric acid, the chirality
It can be supposed that the electron-donating amine group of D form of phenylalanine interacts with the electron-withdrawing imide group of D-perylene bisimide (PBI) (Bettini et al, 2019) and the aromatic moiety of the amino acid interacts with the aromatic ring of the phenylalanine substituent (Giancane et al, 2013; Bettini et al, 2015)
Homochiral substituted perylene with D-phenylalanine was used to selectively discriminate D enantiomer of the amino acid phenylalanine. It was demonstrated by means of spectroscopic techniques, and in particular studying the UV-visible spectrum, that the aggregation state of the D-PBI in water solution is strongly influenced by the presence of D-phenylalanine; on the contrary L-phenylalanine effect is negligible

Summary

Introduction

In the first half of the XIX century Louis Pasteur discovered, during his studies about the optical characteristics of a well-known chemical compound largely investigated in oenology, i.e., the tartaric acid, the chirality. Most known for his important researches on the veterinary medicine, human health, and agriculture, detailed the molecular chirality of the tartaric acid by means of crystallographic and optical activity characterizations starting a new direction in chemistry (Pasteur, 1853; Gal, 2017). Starting from Pasteur’s observations, it was more and more clear that the 3-Dimensional configuration of organic molecules remarkably affects their chemical activity (Xiao et al, 2016). There is a plethora of chiral molecules in nature, with the most characteristic examples being sugars and amino acids (Kabsch and Sander, 1983; Mason, 1984; Klemm et al, 2005). Amino acids exist in two different enantiomers, L and D form, even though is not clear the reason why the Nature almost exclusively use the L enantiomer

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Conclusion