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A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal
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 wit...
Autores principales: | , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380885/ https://www.ncbi.nlm.nih.gov/pubmed/28451368 http://dx.doi.org/10.1039/c6sc05474a |
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author | Tomsett, Michael Maffucci, Irene Le Bailly, Bryden A. F. Byrne, Liam Bijvoets, Stefan M. Lizio, M. Giovanna Raftery, James Butts, Craig P. Webb, Simon J. Contini, Alessandro Clayden, Jonathan |
author_facet | Tomsett, Michael Maffucci, Irene Le Bailly, Bryden A. F. Byrne, Liam Bijvoets, Stefan M. Lizio, M. Giovanna Raftery, James Butts, Craig P. Webb, Simon J. Contini, Alessandro Clayden, Jonathan |
author_sort | Tomsett, Michael |
collection | PubMed |
description | 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. |
format | Online Article Text |
id | pubmed-5380885 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-53808852017-04-27 A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal Tomsett, Michael Maffucci, Irene Le Bailly, Bryden A. F. Byrne, Liam Bijvoets, Stefan M. Lizio, M. Giovanna Raftery, James Butts, Craig P. Webb, Simon J. Contini, Alessandro Clayden, Jonathan Chem Sci Chemistry 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. Royal Society of Chemistry 2017-04-01 2017-01-25 /pmc/articles/PMC5380885/ /pubmed/28451368 http://dx.doi.org/10.1039/c6sc05474a Text en This journal is © The Royal Society of Chemistry 2017 https://creativecommons.org/licenses/by/3.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License (http://creativecommons.org/licenses/by/3.0/ (https://creativecommons.org/licenses/by/3.0/) ) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Chemistry Tomsett, Michael Maffucci, Irene Le Bailly, Bryden A. F. Byrne, Liam Bijvoets, Stefan M. Lizio, M. Giovanna Raftery, James Butts, Craig P. Webb, Simon J. Contini, Alessandro Clayden, Jonathan A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal |
title | A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal
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title_full | A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal
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title_fullStr | A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal
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title_full_unstemmed | A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal
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title_short | A tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal
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title_sort | tendril perversion in a helical oligomer: trapping and characterizing a mobile screw-sense reversal |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380885/ https://www.ncbi.nlm.nih.gov/pubmed/28451368 http://dx.doi.org/10.1039/c6sc05474a |
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