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Krieger V, Ciglia E, Thoma R, Vasylyeva V, Frieg B, de Sousa Amadeu N, Kurz T, Janiak C, Gohlke H, Hansen FK. α- Aminoxy Peptoids: A Unique Peptoid Backbone with a Preference for cis-Amide Bonds. Chemistry 2017; 23:3699-3707. [PMID: 28090689 DOI: 10.1002/chem.201605100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Indexed: 12/13/2022]
Abstract
α-Peptoids, or N-substituted glycine oligomers, are an important class of peptidomimetic foldamers with proteolytic stability. Nevertheless, the presence of cis/trans-amide bond conformers, which contribute to the high flexibility of α-peptoids, is considered as a major drawback. A modified peptoid backbone with an improved control of the amide bond geometry could therefore help to overcome this limitation. Herein, we have performed the first thorough analysis of the folding propensities of α-aminoxy peptoids (or N-substituted 2-aminoxyacetic acid oligomers). To this end, the amide bond geometry and the conformational properties of a series of model α-aminoxy peptoids were investigated by using 1D and 2D NMR experiments, X-ray crystallography, natural bond orbital (NBO) analysis, circular dichroism (CD) spectroscopy, and molecular dynamics (MD) simulations revealing a unique preference for cis-amide bonds even in the absence of cis-directing side chains. The conformational analysis based on the MD simulations revealed that α-aminoxy peptoids can adopt helical conformations that can mimic the spatial arrangement of peptide side chains in a canonical α-helix. Given their ease of synthesis and conformational properties, α-aminoxy peptoids represent a new member of the peptoid family capable of controlling the amide isomerism while maintaining the potential for side-chain diversity.
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Affiliation(s)
- Viktoria Krieger
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Emanuele Ciglia
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Roland Thoma
- Institute of Inorganic and Structural Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Vera Vasylyeva
- Institute of Inorganic and Structural Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Benedikt Frieg
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Nader de Sousa Amadeu
- Institute of Inorganic and Structural Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Thomas Kurz
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Christoph Janiak
- Institute of Inorganic and Structural Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Holger Gohlke
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Finn K Hansen
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany.,Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
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