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Title:Single-conformation IR and UV spectroscopy of a prototypical heterogeneous α/β-peptide: is it a mixed-helix former?
Author(s):Blodgett, Karl N.
Contributor(s):Zwier, Timothy S.; Walsh, Patrick S.
Subject(s):Structure determination
Abstract:Synthetic foldamers are non-natural polymers designed to fold into unique secondary structures that either mimic nature’s preferred secondary structures, or expand their possibilities. Among the most studied synthetic foldamers are $\beta$-peptides, which lengthen the distance between amide groups from the single substituted carbon spacer in $\alpha$-peptides by one additional carbon. We present data on a mixed $\alpha$/$\beta$ tri-peptide in which a single $\beta$-residue with a conformationally constrained cis-2-aminocyclohexanecarboxylic acid (cis-ACHC) substitution is inserted in an $\alpha$-peptide backbone to form Ac-Ala-$\beta$-ACHC-Ala-NHBn. This $\alpha$$\beta$$\alpha$ structure is known in longer sequences to prefer formation of a 9/11 mixed helix. Under isolated, jet cooled conditions, four unique conformers were observed in the expansion. The dominant conformer is configured in a tetramer cycle with every amide carbonyl and amine group involved in hydrogen bonding, giving rise to a tightly folded C12/C7/C8/C7 structure reminiscent of a $\beta$-turn. This talk will describe the conformation specific IR and UV spectroscopy methods used to study this mixed peptide, as well as its experimentally observed conformational preferences.
Issue Date:2016-06-20
Publisher:International Symposium on Molecular Spectroscopy
Genre:Conference Paper/Presentation
Type:Text
Language:En
URI:http://hdl.handle.net/2142/91402
Rights Information:Copyright 2016 by the authors
Date Available in IDEALS:2016-08-22


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