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Special Issue Editor

Prof. Dr. Thomas Schrader

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Guest Editor

Organic Chemistry, Faculty of Chemistry, Duisburg-Essen University, 45117 Essen, Germany
Interests: biosupramolecular chemistry: protein recognition; DNA recognition; artificial signal transduction; broadspectrum antivirals

Special Issue Information

Dear Colleagues,

Since the Nobel Prize in 1987, supramolecular chemistry has considerably matured. However, the construction of functional supramolecular ligands for specific interference with biological systems is still in its infancy. Amino acids are the smallest building blocks for peptides and proteins. The design of artificial ligands with high affinity and selectivity for amino acids and peptides at physiological conditions is a challenging field, since these targets are small, highly polar and therefore well solvated. Peptides are in most cases highly flexible and dynamic; in addition, specific ligands must distinguish between a large number of possible sequences. On the other hand, advanced host molecules may be used for sensing applications and the elucidation of biological mechanisms as well as therapeutic agents. Powerful peptide recognition finally is a prerequisite for the recognition of proteins.

This Special Issue invites the latest contributions in this broad and highly promising field, which combines a long tradition and numerous recent opportunities due to the discovery of new highly active peptides.

Prof. Dr. Thomas Schrader
Guest Editor

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Keywords

Amino Acids
Peptides
Molecular Recognition
Host Molecule
Receptor Molecule
Sensing
Chirality
Medicinal Chemistry

Published Papers (2 papers)

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Research

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13 pages, 3065 KiB

Open AccessArticle

Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders

by Daniel Sebena, Kevin Rudolph, Bibhisan Roy, Christoph Wölper, Till Nitschke, Sarah Lampe, Michael Giese and Jens Voskuhl

Molecules 2022, 27(9), 3005; https://doi.org/10.3390/molecules27093005 - 7 May 2022

Viewed by 1669

Abstract

In this article, we present fluorescent guanidiniocarbonyl-indoles as versatile oxo-anion binders. Herein, the guanidiniocarbonyl-indole (GCI) and methoxy-guanidiniocarbonyl-indole (MGCI) were investigated as ethylamides and compared with the well-known guanidiniocarbonyl-pyrrole (GCP) concerning their photophysical properties as well as their binding behavior towards oxo-anions. Hence, a variety of anionic species, such as carboxylates, phosphonates and sulfonates, have been studied regarding their binding properties with GCP, GCI and MGCI using UV-Vis titrations, in combination with the determination of the complex stoichiometry using the Job method. The emission properties were studied in relation to the pH value using fluorescence spectroscopy as well as the determination of the photoluminescence quantum yields (PLQY). Density functional theory (DFT) calculations were undertaken to obtain a better understanding of the ground-lying electronic properties of the investigated oxo-anion binders. Additionally, X-ray diffraction of GCP and GCI was conducted. We found that GCI and MGCI efficiently bind carboxylates, phosphonates and sulfonates in buffered aqueous solution and in a similar range as GCP (K_ass ≈ 1000–18,000 M⁻¹, in bis-tris buffer, pH = 6); thus, they could be regarded as promising emissive oxo-anion binders. They also exhibit a visible fluorescence with a sufficient PLQY. Additionally, the excitation and emission wavelength of MGCI was successfully shifted closer to the visible region of the electromagnetic spectrum by introducing a methoxy-group into the core structure, which makes them interesting for biological applications. Full article

(This article belongs to the Special Issue Synthetic Receptor Molecules for and with Amino Acids and Peptides)

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Graphical abstract

Review

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35 pages, 11431 KiB

Open AccessReview

Synthetic Receptors Based on Abiotic Cyclo(pseudo)peptides

by Stefan Kubik

Molecules 2022, 27(9), 2821; https://doi.org/10.3390/molecules27092821 - 28 Apr 2022

Cited by 1 | Viewed by 1598

Abstract

Work on the use of cyclic peptides or pseudopeptides as synthetic receptors started even before the field of supramolecular chemistry was firmly established. Research initially focused on the development of synthetic ionophores and involved the use of macrocycles with a repeating sequence of subunits along the ring to facilitate the correlation between structure, conformation, and binding properties. Later, nonnatural amino acids as building blocks were also considered. With growing research in this area, cyclopeptides and related macrocycles developed into an important and structurally diverse receptor family. This review provides an overview of these developments, starting from the early years. The presented systems are classified according to characteristic structural elements present along the ring. Wherever possible, structural aspects are correlated with binding properties to illustrate how natural or nonnatural amino acids affect binding properties. Full article

(This article belongs to the Special Issue Synthetic Receptor Molecules for and with Amino Acids and Peptides)

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