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Tomsett M, Maffucci I, Le Bailly BAF, Byrne L, Bijvoets SM, Lizio MG, Raftery J, Butts CP, Webb SJ, Contini A, Clayden J. A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal. Chem Sci 2017; 8:3007-3018. [PMID: 28451368 PMCID: PMC5380885 DOI: 10.1039/c6sc05474a] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 01/24/2017] [Indexed: 11/21/2022] Open
Abstract
Helical oligomers of achiral monomers adopt domains of uniform screw sense, which are occasionally interrupted by screw-sense reversals. These rare, elusive, and fast-moving features have eluded detailed characterization. We now describe the structure and habits of a screw-sense reversal trapped within a fragment of a helical oligoamide foldamer of the achiral quaternary amino acid 2-aminoisobutyric acid (Aib). The reversal was enforced by compelling the amide oligomer to adopt a right-handed screw sense at one end and a left-handed screw sense at the other. The trapped reversal was characterized by X-ray crystallography, and its dynamic properties were monitored by NMR and circular dichroism, and modelled computationally. Raman spectroscopy indicated that a predominantly helical architecture was maintained despite the reversal. NMR and computational results indicated a stepwise shift from one screw sense to another on moving along the helical chain, indicating that in solution the reversal is not localised at a specific location, but is free to migrate across a number of residues. Analogous unconstrained screw-sense reversals that are free to move within a helical structure are likely to provide the mechanism by which comparable helical polymers and foldamers undergo screw-sense inversion.
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Affiliation(s)
- Michael Tomsett
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - Irene Maffucci
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini" , Università degli Studi di Milano , Via Venezian , 21 20133 Milano , Italy
| | - Bryden A F Le Bailly
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - Liam Byrne
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK
| | - Stefan M Bijvoets
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK
| | - M Giovanna Lizio
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK.,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
| | - James Raftery
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK
| | - Craig P Butts
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - Simon J Webb
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK.,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
| | - Alessandro Contini
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini" , Università degli Studi di Milano , Via Venezian , 21 20133 Milano , Italy
| | - Jonathan Clayden
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
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Jewgiński M, Krzciuk-Gula J, Makowski M, Latajka R, Kafarski P. Conformation of dehydropentapeptides containing four achiral amino acid residues - controlling the role of L-valine. Beilstein J Org Chem 2014; 10:660-6. [PMID: 24778717 PMCID: PMC3999861 DOI: 10.3762/bjoc.10.58] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/05/2014] [Indexed: 12/01/2022] Open
Abstract
Structural studies of pentapeptides containing an achiral block, built from two dehydroamino acid residues (ΔZPhe and ΔAla) and two glycines, as well as one chiral L-Val residue were performed using NMR spectroscopy. The key role of the L-Val residue in the generation of the secondary structure of peptides is discussed. The obtained results suggest that the strongest influence on the conformation of peptides arises from a valine residue inserted at the C-terminal position. The most ordered conformation was found for peptide Boc-Gly-ΔAla-Gly-ΔZPhe-Val-OMe (3), which adopts a right-handed helical conformation.
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Affiliation(s)
- Michał Jewgiński
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Joanna Krzciuk-Gula
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Maciej Makowski
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052 Opole, Poland
| | - Rafał Latajka
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Paweł Kafarski
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
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Inai Y, Kurokawa Y, Hirabayashi T. Solvent Dependence on the Preference of Helical Screw Sense: Effect of l-Leu Residue Second from N-Terminal on Screw Sense in Achiral Peptide. Macromolecules 1999. [DOI: 10.1021/ma9901442] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yoshihito Inai
- Department of Environmental Technology and Urban Planning, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Yuji Kurokawa
- Department of Environmental Technology and Urban Planning, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Tadamichi Hirabayashi
- Department of Environmental Technology and Urban Planning, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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