Single-conformation IR and UV spectroscopy of a prototypical heterogeneous α/β-peptide: is it a mixed-helix former?

Blodgett, Karl N.

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https://hdl.handle.net/2142/91402 Copy

Description

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.

Issue Date

2016-06-20

Keyword(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.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

En

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http://hdl.handle.net/2142/91402

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Copyright 2016 by the authors

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