1
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Picois N, Bodero L, Milbeo P, Brigaud T, Chaume G. Bimodal Use of Chiral α-Trifluoromethylalanine in Aib Foldamers: Study of the Position Impact Towards the Helical Screw-Sense Preference. Chemistry 2024; 30:e202400540. [PMID: 38445775 DOI: 10.1002/chem.202400540] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 02/07/2024] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/07/2024]
Abstract
Oligomers of the achiral α-aminoisobutyric acid (Aib) adopt a 310 helical conformation in which the screw-sense preference can be controlled by a single chiral residue. The use of the fluorinated residue α-Trifluoromethylalanine (α-TfmAla) revealed a unique way to both induce and measure the screw-sense preference of such oligomers acting as 19F NMR probe. This work proposes a systematic study of the effect of this fluorinated chiral inducer on the helical screw-sense preference of poly-Aib oligomers. The impact of the position of the fluorinated residue into pentamers (N-terminal, central or C-terminal) as well as the nature of the C-terminal capping of the peptides was thoroughly studied in light of complete structural analysis. A deeper understanding of the fluorine effect was achieved confirming the unique ability of α-TfmAla as a helical screw-sense controller.
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Affiliation(s)
- Nathan Picois
- CY Cergy Paris Université, CNRS, BioCIS, 95000, Cergy Pontoise, France
- Université Paris-Saclay, CNRS, BioCIS, 91400, Orsay, France
| | - Lizeth Bodero
- CY Cergy Paris Université, CNRS, BioCIS, 95000, Cergy Pontoise, France
- Université Paris-Saclay, CNRS, BioCIS, 91400, Orsay, France
| | - Pierre Milbeo
- CY Cergy Paris Université, CNRS, BioCIS, 95000, Cergy Pontoise, France
- Université Paris-Saclay, CNRS, BioCIS, 91400, Orsay, France
| | - Thierry Brigaud
- CY Cergy Paris Université, CNRS, BioCIS, 95000, Cergy Pontoise, France
- Université Paris-Saclay, CNRS, BioCIS, 91400, Orsay, France
| | - Grégory Chaume
- CY Cergy Paris Université, CNRS, BioCIS, 95000, Cergy Pontoise, France
- Université Paris-Saclay, CNRS, BioCIS, 91400, Orsay, France
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2
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Tilly DP, McColl C, Hu M, Vitórica-Yrezábal IJ, Webb SJ. Enantioselective conjugate addition to nitroolefins catalysed by helical peptides with a single remote stereogenic centre. Org Biomol Chem 2023; 21:9562-9571. [PMID: 38009076 DOI: 10.1039/d3ob01594g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
Two short pentapeptides rich in α-aminoisobutyric acid (Aib) residues have been shown to act as enantioselective organocatalysts for the conjugate addition of nucleophiles to nitroolefins. An L-alanine terminated peptide, (Aib)4(L-Ala)NHtBu, which has neither functionalised sidechains nor a highly designed reactive site, used an exposed N-terminal primary amine and the amide bonds of the backbone to mediate catalysis. Folding of this peptide into a 310 helical structure was observed by crystallography. Folding into a helix relays the conformational preference of the chiral alanine residue at the C-terminus to the primary amine at the N-terminus, 0.9 nm distant. The chiral environment and defined shape produced by the 310 helix brings the amine site into proximity to two exposed amide NHs. Reaction scope studies implied that the amine acts as a Brønsted base and the solvent-exposed NH groups of the helix, shown to weakly bind β-nitrostyrene, are needed to obtain an enantiomeric excess. Replacement of L-alanine with D-phenylalanine gave (Aib)4(D-Phe)NHtBu, a peptide that now catalysed the benchmark reaction with the opposite enantioselectivity. These studies show how achiral residues can play a key role in enantioselective catalysis by peptides through the promotion of folding.
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Affiliation(s)
- David P Tilly
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Catherine McColl
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Mingda Hu
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | | | - Simon J Webb
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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3
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Pike SJ, Telford R, Male L. Reversible conformational switching of a photo-responsive ortho-azobenzene/2,6-pyridyldicarboxamide heterofoldamer. Org Biomol Chem 2023; 21:7717-7723. [PMID: 37565617 DOI: 10.1039/d3ob01137b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
We report on a convenient synthetic route to rapidly access a new photo-responsive ortho-azobenzene/2,6-pyridyldicarboxamide heterofoldamer. The adoption of a stable helical conformation has been established for this scaffold in both the solid state and in solution using single crystal X-ray diffraction and circular dichroism (CD) spectroscopy respectively. Reversible control over the stimuli-driven structural re-ordering of the supramolecular scaffold, from a stable helical conformation under non-irradiative conditions, to a less well-ordered state under irradiative conditions, has been identified. The robust nature of the responsive, conformational, molecular switching behaviour has been determined using UV/Vis, 1H NMR and CD spectroscopy. Minimal loss in the efficiency of the stimuli-driven, structural re-ordering processes of the foldamer scaffold is observed, even upon multiple cyclic treatments with irradiative/non-irradiative conditions.
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Affiliation(s)
- Sarah J Pike
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- School of Chemistry and Biosciences, Faculty of Life Sciences, University of Bradford, Bradford, West Yorkshire, BD7 1DP, UK
| | - Richard Telford
- School of Chemistry and Biosciences, Faculty of Life Sciences, University of Bradford, Bradford, West Yorkshire, BD7 1DP, UK
| | - Louise Male
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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4
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Shen H, Tang X, Wu Q, Zhang Y, Ma C, Xu Z, Teo BK, Zheng N. Guiding the High-Yield Synthesis of NHC-Ligated Gold Nanoclusters by 19F NMR Spectroscopy. ACS Nanosci Au 2022; 2:520-526. [PMID: 37101850 PMCID: PMC10125265 DOI: 10.1021/acsnanoscienceau.2c00026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 04/28/2023]
Abstract
Optimizing the synthesis of atomically precise metal nanoclusters by virtue of molecular tools is highly desirable but quite challenging. Herein we report how 19F NMR spectroscopy can be used to guide the high-yield synthesis of N-heterocyclic carbene (NHC)-stabilized gold nanoclusters. In spite of little difference, 19F NMR signals of fluoro-incorporated NHCs (FNHC) are highly sensitive to the tiny change in their surrounding chemical environments with different N-substituents, metals, or anions, thus providing a convenient strategy to discriminate species in reaction mixtures. By using 19F NMR, we first disclosed that the one-pot reduction of FNHC-Au-X (X is halide) yields multiple compounds, including cluster compounds and also a large amount of highly stable [Au(FNHC)2]+ byproduct. The detailed quantitative 19F NMR analyses over the reductive synthesis of NHC-stabilized Au nanoclusters reveal that the formation of the di-NHC complex is deleterious to the high-yield synthesis of NHC-stabilized Au nanoclusters. With the understanding, the reaction kinetic was then slowed by controlling the reduction rate to achieve the high yield of a [Au24(FNHC)14X2H3]3+ nanocluster with a unique structure. The strategy demonstrated in this work is expected to provide an effective tool to guide the high-yield synthesis of organic ligand-stabilized metal nanoclusters.
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Affiliation(s)
- Hui Shen
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiongkai Tang
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Qingyuan Wu
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yuhao Zhang
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chuxin Ma
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhen Xu
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Boon K. Teo
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Nanfeng Zheng
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative
Innovation Center of Chemistry for Energy Materials, and National
& Local Joint Engineering Research Center for Preparation Technology
of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- Innovation
Laboratory for Sciences and Technologies of Energy Materials of Fujian
Province (IKKEM), Xiamen 361005, China
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5
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Wang S, della Sala F, Cliff MJ, Whitehead GFS, Vitórica-Yrezábal IJ, Webb SJ. Chiral 19F NMR Reporter of Foldamer Conformation in Bilayers. J Am Chem Soc 2022; 144:21648-21657. [DOI: 10.1021/jacs.2c09103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Siyuan Wang
- Department of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, ManchesterM1 7DN, U.K
| | - Flavio della Sala
- Department of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, ManchesterM1 7DN, U.K
| | - Matthew J. Cliff
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, ManchesterM1 7DN, U.K
| | | | | | - Simon J. Webb
- Department of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, ManchesterM1 7DN, U.K
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6
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Tilly DP, Cullen W, Zhong H, Jamagne R, Vitórica-Yrezábal I, Webb SJ. α-Amino-iso-butyric acid foldamers terminated with rhodium(I) N-heterocyclic carbene catalysts. Chemistry 2021; 28:e202104293. [PMID: 34932229 PMCID: PMC9305545 DOI: 10.1002/chem.202104293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Indexed: 12/01/2022]
Abstract
To investigate how remotely induced changes in ligand folding might affect catalysis by organometallic complexes, dynamic α‐amino‐iso‐butyric acid (Aib) peptide foldamers bearing rhodium(I) N‐heterocyclic carbene (NHC) complexes have been synthesized and studied. X‐ray crystallography of a foldamer with an N‐terminal azide and a C‐terminal Rh(NHC)(Cl)(diene) complex showed a racemate with a chiral axis in the Rh(NHC) complex and a distorted 310 helical body. Replacing the azide with either one or two chiral L‐α‐methylvaline (L‐αMeVal) residues gave diastereoisomeric foldamers that each possessed point, helical and axial chirality. NMR spectroscopy revealed an unequal ratio of diastereoisomers for some foldamers, indicating that the chiral conformational preference of the N‐terminal residue(s) was relayed down the 1 nm helical body to the axially chiral Rh(NHC) complex. Although the remote chiral residue(s) did not affect the stereoselectivity of hydrosilylation reactions catalysed by these foldamers, these studies suggest a potential pathway towards remote conformational control of organometallic catalysts.
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Affiliation(s)
- David P Tilly
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | - William Cullen
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | - Heng Zhong
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | - Romain Jamagne
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | | | - Simon John Webb
- University of Manchester, School of Chemistry and MIB, 131 Princess St, M1 7DN, Manchester, UNITED KINGDOM
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7
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Bodero L, Guitot K, Lensen N, Lequin O, Brigaud T, Ongeri S, Chaume G. Introducing the Chiral Constrained α-Trifluoromethylalanine in Aib foldamers to Control, Quantify and Assign the Helical Screw-Sense. Chemistry 2021; 28:e202103887. [PMID: 34890083 DOI: 10.1002/chem.202103887] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 10/28/2021] [Indexed: 11/11/2022]
Abstract
Oligomers of α-aminoisobutyric acid (Aib) are achiral peptides that adopt 3 10 helical structures with equal population of left- and right-handed conformers. Yet, the screw-sense preference of the helical chain may be controlled by a single chiral residue located at one terminus. 1 H and 19 F NMR, X-ray crystallography and circular dichroism studies on new Aib oligomers show that the incorporation of a chiral quaternary α-trifluoromethylalanine at their N -terminus induces a reversal of the screw-sense preference of the 3 10 -helix compared to that of a non-fluorinated analogue having an l-α-methyl valine residue. This work demonstrates that, among the many particular properties of introducing a trifluoromethyl group into foldamers, its stereo-electronic properties are of major interest to control the helical screw sense. Its use as an easy-to-handle 19 F NMR probe to reliably determine both the magnitude of the screw-sense preference and its sign assignment is also of remarkable interest.
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Affiliation(s)
| | | | | | - Olivier Lequin
- Sorbonne Université Campus Pierre et Marie Curie: Sorbonne Universite Campus Pierre et Marie Curie, chemistry, FRANCE
| | | | | | - Grégory Chaume
- CY Cergy Paris Universite, Chemistry, 5 mail Gay Lussac, 95000, Cergy-Pontoise, FRANCE
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8
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Abudken AMH, Hope EG, Singh K, Stuart AM. Fluorinations of unsymmetrical diaryliodonium salts containing ortho-sidearms; influence of sidearm on selectivity. Org Biomol Chem 2020; 18:6140-6146. [PMID: 32724955 DOI: 10.1039/d0ob01401j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Activated aromatics were reacted with two different fluoroidoane reagents 1 and 2 in the presence of triflic acid to prepare only the para-substituted diaryliodonium salts. With fluoroiodane 1 the unsymmetrical diaryliodonium salts contained an ortho-propan-2-ol sidearm, whereas the alcohol sidearm was eliminated to form an ortho-styrene sidearm in the reaction with fluoroiodane 2. Only the diaryliodonium salts containing a styrene sidearm were fluorinated successfully to deliver para-fluorinated aromatics in good yields.
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Affiliation(s)
- Ahmed M H Abudken
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK. and College of Pharmacy, Al-Qadisiyah University, Al-Qadisiyah, Iraq
| | - Eric G Hope
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.
| | - Kuldip Singh
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.
| | - Alison M Stuart
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.
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9
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Eccles N, della Sala F, Le Bailly BAF, Whitehead GFS, Clayden J, Webb SJ. Molecular Recognition by Zn(II)-Capped Dynamic Foldamers. ChemistryOpen 2020; 9:338-345. [PMID: 32195074 PMCID: PMC7080544 DOI: 10.1002/open.201900362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/05/2020] [Indexed: 11/29/2022] Open
Abstract
Two α-aminoisobutyric acid (Aib) foldamers bearing Zn(II)-chelating N-termini have been synthesized and compared with a reported Aib foldamer that has a bis(quinolinyl)/mono(pyridyl) cap (BQPA group). Replacement of the quinolinyl arms of the BQPA-capped foldamer with pyridyl gave a BPPA-capped foldamer, then further replacement of the linking pyridyl with a 1,2,3-triazole gave a BPTA-capped foldamer. Their ability to relay chiral information from carboxylate bound to Zn(II) at the N-terminus to a glycinamide-based NMR reporter of conformational preference at the C-terminus was measured. The importance of the quinolinyl arms became readily apparent, as the foldamers with pyridyl arms were unable to report on the presence of chiral carboxylate in acetonitrile. Low solubility, X-ray crystallography and 1H NMR spectroscopy suggested that interfoldamer interactions inhibited carboxylate binding. However changing solvent to methanol revealed that the end-to-end relay of chiral information could be observed for the Zn(II) complex of the BPTA-capped foldamer at low temperature.
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Affiliation(s)
- Natasha Eccles
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
- Manchester Institute of BiotechnologyUniversity of Manchester131 Princess StManchesterM1 7DNUK
| | - Flavio della Sala
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
- Manchester Institute of BiotechnologyUniversity of Manchester131 Princess StManchesterM1 7DNUK
| | - Bryden A. F. Le Bailly
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | | | - Jonathan Clayden
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Simon J. Webb
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
- Manchester Institute of BiotechnologyUniversity of Manchester131 Princess StManchesterM1 7DNUK
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10
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Eccles N, Le Bailly BAF, Della Sala F, Vitórica-Yrezábal IJ, Clayden J, Webb SJ. Remote conformational responses to enantiomeric excess in carboxylate-binding dynamic foldamers. Chem Commun (Camb) 2019; 55:9331-9334. [PMID: 31313773 DOI: 10.1039/c9cc03895g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A crystallographically characterised zinc(ii)-capped foldamer can sense the enantiomeric excess of scalemic carboxylate solutions, including those produced by enantioselective organocatalysis, and can relay this input signal along the foldamer body to a remote glycinamide group, which then provides an NMR spectroscopic output.
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Affiliation(s)
- Natasha Eccles
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK and Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester M1 7DN, UK.
| | - Bryden A F Le Bailly
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK and School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Flavio Della Sala
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK and Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester M1 7DN, UK.
| | | | - Jonathan Clayden
- 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 and Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester M1 7DN, UK.
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11
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Biggs GS, O'Neill MJ, Carames Mendez P, Scrase TG, Lin Y, Bin-Maarof AM, Bond AD, Boss SR, Barker PD. Use of a fluorinated probe to quantitatively monitor amino acid binding preferences of ruthenium(ii) arene complexes. Dalton Trans 2019; 48:6910-6920. [DOI: 10.1039/c8dt05159c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Speciation of Ru(ii) arene complexes in mixtures of amino acids with coordinating sidechains is easily resolved by 19F NMR.
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Affiliation(s)
- George S. Biggs
- University of Cambridge
- Chemistry Department
- Cambridge CB2 1EW
- UK
| | - Michael J. O'Neill
- University of Cambridge
- Chemistry Department
- Cambridge CB2 1EW
- UK
- Faculty of Science and Engineering School of Mathematics and Physical Sciences
| | | | | | - Yulu Lin
- University of Cambridge
- Chemistry Department
- Cambridge CB2 1EW
- UK
| | | | - Andrew D. Bond
- University of Cambridge
- Chemistry Department
- Cambridge CB2 1EW
- UK
| | - Sally R. Boss
- University of Cambridge
- Chemistry Department
- Cambridge CB2 1EW
- UK
| | - Paul D. Barker
- University of Cambridge
- Chemistry Department
- Cambridge CB2 1EW
- UK
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12
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Lister FGA, Eccles N, Pike SJ, Brown RA, Whitehead GFS, Raftery J, Webb SJ, Clayden J. Bis-pyrene probes of foldamer conformation in solution and in phospholipid bilayers. Chem Sci 2018; 9:6860-6870. [PMID: 30310619 PMCID: PMC6114994 DOI: 10.1039/c8sc02532k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/16/2018] [Indexed: 11/21/2022] Open
Abstract
Exploring the detailed structural features of synthetic molecules in the membrane phase requires sensitive probes of conformation. Here we describe the design, synthesis and characterization of bis(pyrene) probes that report conformational changes in membrane-active dynamic foldamers. The probes were designed to distinguish between left-handed (M) and right-handed (P) screw-sense conformers of 310-helical α-aminoisobutyric acid (Aib) peptide foldamers, both in solution and in bilayer membranes. Several different bis(pyrene) probes were synthesized and ligated to the C-terminus of Aib tetramers that had different chiral residues at the N-terminus, residues that favored either an M or a P screw-sense in the 310-helix. The readily synthesized and conveniently incorporated N-acetyl-1,2-bis(pyren-1'-yl)ethylenediamine probe proved to have the best properties. In solution, changes in foldamer screw-sense induced substantial changes in the ratio of excimer/monomer fluorescence emission (E/M) for this reporter of conformation, with X-ray crystallography revealing that opposite screw-senses produce very different interpyrene distances in the reporter. In bilayers, this convenient and sensitive fluorescent reporter allowed, for the first time, an investigation of how the chirality of natural phospholipids affects foldamer conformation.
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Affiliation(s)
- Francis G A Lister
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - Natasha Eccles
- 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
| | - Sarah J Pike
- 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.,Faculty of Life Sciences , University of Bradford , Bradford , West Yorkshire BD7 1DP , UK
| | - Robert A Brown
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - George F S Whitehead
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - James Raftery
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , 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
| | - Jonathan Clayden
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
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13
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García-Pérez D, López C, Claramunt RM, Alkorta I, Elguero J. 19F-NMR Diastereotopic Signals in Two N-CHF₂ Derivatives of (4S,7R)-7,8,8-Trimethyl-4,5,6,7-tetrahydro-4,7-methano-2H-indazole. Molecules 2017; 22:E2003. [PMID: 29149081 PMCID: PMC6150283 DOI: 10.3390/molecules22112003] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 11/17/2022] Open
Abstract
In this paper, we report the anisochrony of the fluorine atoms of a CHF₂ group when linked to a pyrazole ring. The pyrazole is part of (4S,7R)-7,8,8-trimethyl-4,5,6,7-tetrahydro-4,7-methano-2H-indazole also known as (4S,7R)-campho[2,3-c]pyrazole, which has two stereogenic centers. Gauge-Independent Atomic Orbital (GIAO)/Becke, 3-parameter, Lee-Yang-Parr (B3LYP)/6-311++G(d,f) calculated 19F chemical shifts of the minimum energy conformations satisfactorily agree with the experimental data. The energy differences between minima need to consider solvent effects (continuum model) to be satisfactorily reproduced.
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Affiliation(s)
- Diana García-Pérez
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Senda del Rey 9, E-28040 Madrid, Spain.
| | - Concepción López
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Senda del Rey 9, E-28040 Madrid, Spain.
| | - Rosa M Claramunt
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Senda del Rey 9, E-28040 Madrid, Spain.
| | - Ibon Alkorta
- Instituto de Química Médica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain.
| | - José Elguero
- Instituto de Química Médica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain.
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14
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Diemer V, Maury J, Le Bailly BAF, Webb SJ, Clayden J. Dibenzazepinyl ureas as dual NMR and CD probes of helical screw-sense preference in conformationally equilibrating dynamic foldamers. Chem Commun (Camb) 2017; 53:10768-10771. [DOI: 10.1039/c7cc06427f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Dibenzazepinyl ureas act as probes to allow conformational analysis of screw-sense preference in dynamic foldamers by both NMR and CD spectroscopy.
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Affiliation(s)
- Vincent Diemer
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
| | - Julien Maury
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
| | | | - Simon J. Webb
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
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15
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Pike SJ, Jones JE, Raftery J, Clayden J, Webb SJ. Helical peptaibol mimics are better ionophores when racemic than when enantiopure. Org Biomol Chem 2016; 13:9580-4. [PMID: 26327434 DOI: 10.1039/c5ob01652e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helical peptide foldamers rich in α-aminoisobutyric acid (Aib) act as peptaibol-mimicking ionophores in the phospholipid bilayers of artificial vesicles. Racemic samples of these foldamers are more active than their enantiopure counterparts, which was attributed to differing propensities to form aggregates with crystal-like features in the bilayer.
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Affiliation(s)
- Sarah J Pike
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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16
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Pike SJ, Raftery J, Webb SJ, Clayden J. Conformational analysis of helical aminoisobutyric acid (Aib) oligomers bearing C-terminal ester Schellman motifs. Org Biomol Chem 2016; 12:4124-31. [PMID: 24831537 DOI: 10.1039/c4ob00268g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of Schellman motifs on the adoption of stable 310 helical conformations in a series of aminoisobutyric (Aib) oligomers has been studied in the solid state and solution. The destabilising effect of the Schellman motif (a local inversion of helical screw-sense due to a C-terminal ester residue) was quantified in the solid state using X-ray crystallography through analysis of the torsion angles and their deviation from those observed in an ideal 310 helix. Investigation of the intramolecular hydrogen-bonding interactions in the solid state led to the identification of a fully extended C5 conformation in one oligomer, which is a novel folding motif for Aib oligomers. The effect of ester groups with differing steric demands on intermolecular hydrogen-bonding contacts in the solid state was also ascertained. In solution, the adoption of a 310 conformation in Aib oligomers appeared to be more finely tuned, depending on a number of factors, including chain length and the steric demands of the C-terminal destabilising Schellman motif.
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Affiliation(s)
- Sarah J Pike
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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17
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De Poli M, Zawodny W, Quinonero O, Lorch M, Webb SJ, Clayden J. Conformational photoswitching of a synthetic peptide foldamer bound within a phospholipid bilayer. Science 2016; 352:575-80. [PMID: 27033546 DOI: 10.1126/science.aad8352] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/24/2016] [Indexed: 12/17/2022]
Abstract
The dynamic properties of foldamers, synthetic molecules that mimic folded biomolecules, have mainly been explored in free solution. We report on the design, synthesis, and conformational behavior of photoresponsive foldamers bound in a phospholipid bilayer akin to a biological membrane phase. These molecules contain a chromophore, which can be switched between two configurations by different wavelengths of light, attached to a helical synthetic peptide that both promotes membrane insertion and communicates conformational change along its length. Light-induced structural changes in the chromophore are translated into global conformational changes, which are detected by monitoring the solid-state (19)F nuclear magnetic resonance signals of a remote fluorine-containing residue located 1 to 2 nanometers away. The behavior of the foldamers in the membrane phase is similar to that of analogous compounds in organic solvents.
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Affiliation(s)
- Matteo De Poli
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Wojciech Zawodny
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Ophélie Quinonero
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Mark Lorch
- Department of Chemistry, University of Hull, Hull HU6 7RX, UK
| | - Simon J Webb
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK. Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
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18
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Abstract
Foldamers can be made more than pieces of static, conformationally uniform molecular architecture by designing into their structure the conformational dynamism characteristic of functional molecular machines. We show that these dynamic foldamers display biomimetic properties reminiscent of allosteric proteins and receptor molecules. They can translate chemical signals into conformational changes, and hence into chemical outputs such as control of reactivity and selectivity. Future developments could see dynamic foldamers operating in the membrane phase providing artificial mechanisms for communication and control that integrate synthetic chemistry into synthetic biology.
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Affiliation(s)
- Bryden A F Le Bailly
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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19
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Jones JE, Diemer V, Adam C, Raftery J, Ruscoe RE, Sengel JT, Wallace MI, Bader A, Cockroft SL, Clayden J, Webb SJ. Length-Dependent Formation of Transmembrane Pores by 310-Helical α-Aminoisobutyric Acid Foldamers. J Am Chem Soc 2016; 138:688-95. [PMID: 26699898 PMCID: PMC4752191 DOI: 10.1021/jacs.5b12057] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
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The synthetic biology toolbox lacks
extendable and conformationally
controllable yet easy-to-synthesize building blocks that are long
enough to span membranes. To meet this need, an iterative synthesis
of α-aminoisobutyric acid (Aib) oligomers was used to create
a library of homologous rigid-rod 310-helical foldamers,
which have incrementally increasing lengths and functionalizable N-
and C-termini. This library was used to probe the inter-relationship
of foldamer length, self-association strength, and ionophoric ability,
which is poorly understood. Although foldamer self-association in
nonpolar chloroform increased with length, with a ∼14-fold
increase in dimerization constant from Aib6 to Aib11, ionophoric activity in bilayers showed a stronger length
dependence, with the observed rate constant for Aib11 ∼70-fold
greater than that of Aib6. The strongest ionophoric activity
was observed for foldamers with >10 Aib residues, which have end-to-end
distances greater than the hydrophobic width of the bilayers used
(∼2.8 nm); X-ray crystallography showed that Aib11 is 2.93 nm long. These studies suggest that being long enough to
span the membrane is more important for good ionophoric activity than
strong self-association in the bilayer. Planar bilayer conductance
measurements showed that Aib11 and Aib13, but
not Aib7, could form pores. This pore-forming behavior
is strong evidence that Aibm (m ≥ 10) building blocks can span bilayers.
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Affiliation(s)
- Jennifer E Jones
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.,Manchester Institute of Biotechnology, University of Manchester , 131 Princess St, Manchester M1 7DN, United Kingdom
| | - Vincent Diemer
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.,Manchester Institute of Biotechnology, University of Manchester , 131 Princess St, Manchester M1 7DN, United Kingdom
| | - Catherine Adam
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.,School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - James Raftery
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Rebecca E Ruscoe
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Jason T Sengel
- Department of Chemistry, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Mark I Wallace
- Department of Chemistry, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Antoine Bader
- EaStCHEM School of Chemistry, University of Edinburgh , Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Scott L Cockroft
- EaStCHEM School of Chemistry, University of Edinburgh , Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Jonathan Clayden
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.,School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Simon J Webb
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.,Manchester Institute of Biotechnology, University of Manchester , 131 Princess St, Manchester M1 7DN, United Kingdom
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20
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Brioche J, Pike S, Tshepelevitsh S, Leito I, Morris GA, Webb SJ, Clayden J. Conformational Switching of a Foldamer in a Multicomponent System by pH-Filtered Selection between Competing Noncovalent Interactions. J Am Chem Soc 2015; 137:6680-91. [PMID: 25915163 PMCID: PMC4520694 DOI: 10.1021/jacs.5b03284] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Indexed: 12/26/2022]
Abstract
Biomolecular systems are able to respond to their chemical environment through reversible, selective, noncovalent intermolecular interactions. Typically, these interactions induce conformational changes that initiate a signaling cascade, allowing the regulation of biochemical pathways. In this work, we describe an artificial molecular system that mimics this ability to translate selective noncovalent interactions into reversible conformational changes. An achiral but helical foldamer carrying a basic binding site interacts selectively with the most acidic member of a suite of chiral ligands. As a consequence of this noncovalent interaction, a global absolute screw sense preference, detectable by (13)C NMR, is induced in the foldamer. Addition of base, or acid, to the mixture of ligands competitively modulates their interaction with the binding site, and reversibly switches the foldamer chain between its left and right-handed conformations. As a result, the foldamer-ligand mixture behaves as a biomimetic chemical system with emergent properties, functioning as a "proton-counting" molecular device capable of providing a tunable, pH-dependent conformational response to its environment.
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Affiliation(s)
- Julien Brioche
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - Sarah
J. Pike
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - Sofja Tshepelevitsh
- Institute
of Chemistry, University of Tartu, Ravila 14a, Tartu 50411, Estonia
| | - Ivo Leito
- Institute
of Chemistry, University of Tartu, Ravila 14a, Tartu 50411, Estonia
| | - Gareth A. Morris
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - Simon J. Webb
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
- Manchester
Institute of Biotechnology, University of
Manchester, 131 Princess
Street, Manchester M1 7DN, United Kingdom
| | - Jonathan Clayden
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
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21
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Le Bailly BAF, Clayden J. Controlling the sign and magnitude of screw-sense preference from the C-terminus of an achiral helical foldamer. Chem Commun (Camb) 2015; 50:7949-52. [PMID: 24918692 DOI: 10.1039/c4cc03261f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The global screw-sense preference of an achiral helical oligomer may be controlled by a single chiral monomer located at one terminus. Remarkably, maximal control is induced in oligomers of the achiral quaternary amino acid Aib by a single C-terminal alaninamide residue, probably because the Ala side chain, though small, is compatible with a 310 helical conformation. The presence or absence of a C-terminal hydrogen bond donor determines the screw sense of the entire oligomer.
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Affiliation(s)
- Bryden A F Le Bailly
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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22
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Le Bailly BAF, Byrne L, Diemer V, Foroozandeh M, Morris GA, Clayden J. Flaws in foldamers: conformational uniformity and signal decay in achiral helical peptide oligomers. Chem Sci 2015; 6:2313-2322. [PMID: 29308146 PMCID: PMC5645781 DOI: 10.1039/c4sc03944k] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 01/19/2015] [Indexed: 11/21/2022] Open
Abstract
Although foldamers, by definition, are extended molecular structures with a well-defined conformation, minor conformers must be populated at least to some extent in solution. We present a quantitative analysis of these minor conformers for a series of helical oligomers built from achiral but helicogenic α-amino acids. By measuring the chain length dependence or chain position dependence of NMR or CD quantities that measure screw-sense preference in a helical oligomer, we quantify values for the decay constant of a conformational signal as it passes through the molecular structure. This conformational signal is a perturbation of the racemic mixture of M and P helices that such oligomers typically adopt by the inclusion of an N or C terminal chiral inducer. We show that decay constants may be very low (<1% signal loss per residue) in non-polar solvents, and we evaluate the increase in decay constant that results in polar solvents, at higher temperatures, and with more conformationally flexible residues such as Gly. Decay constants are independent of whether the signal originates from the N or the C terminus. By interpreting the decay constant in terms of the probability with which conformations containing a screw-sense reversal are populated, we quantify the populations of these alternative minor conformers within the overall ensemble of secondary structures adopted by the foldamer. We deduce helical persistence lengths for Aib polymers that allow us to show that in a non-polar solvent a peptide helix, even in the absence of chiral residues, may continue with the same screw sense for approximately 200 residues.
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Affiliation(s)
- Bryden A F Le Bailly
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - Liam Byrne
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - Vincent Diemer
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | | | - Gareth A Morris
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - Jonathan Clayden
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
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23
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Alkorta I, Dardonville C, Elguero J. Observation of Diastereotopic Signals in 15N NMR Spectroscopy. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201412144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Alkorta I, Dardonville C, Elguero J. Observation of Diastereotopic Signals in15N NMR Spectroscopy. Angew Chem Int Ed Engl 2015; 54:3997-4000. [DOI: 10.1002/anie.201412144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Indexed: 11/08/2022]
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25
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Crisma M, De Zotti M, Formaggio F, Peggion C, Moretto A, Toniolo C. Handedness preference and switching of peptide helices. Part II: Helices based on noncodedα-amino acids. J Pept Sci 2015; 21:148-77. [DOI: 10.1002/psc.2743] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/19/2014] [Accepted: 12/19/2014] [Indexed: 12/27/2022]
Affiliation(s)
| | - Marta De Zotti
- Department of Chemistry; University of Padova; Padova Italy
| | - Fernando Formaggio
- ICB; Padova Unit; CNR Padova Italy
- Department of Chemistry; University of Padova; Padova Italy
| | | | - Alessandro Moretto
- ICB; Padova Unit; CNR Padova Italy
- Department of Chemistry; University of Padova; Padova Italy
| | - Claudio Toniolo
- ICB; Padova Unit; CNR Padova Italy
- Department of Chemistry; University of Padova; Padova Italy
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26
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Pike SJ, Boddaert T, Raftery J, Webb SJ, Clayden J. Participation of non-aminoisobutyric acid (Aib) residues in the 310 helical conformation of Aib-rich foldamers: a solid state study. NEW J CHEM 2015. [DOI: 10.1039/c4nj01547a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
310 helical conformations that extend over 21 Å result when selected non-Aib terminal and central residues are incorporated into Aib-rich foldamers.
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Affiliation(s)
- Sarah J. Pike
- School of Chemistry
- University of Manchester
- Manchester
- UK
| | | | - James Raftery
- School of Chemistry
- University of Manchester
- Manchester
- UK
| | - Simon J. Webb
- School of Chemistry
- University of Manchester
- Manchester
- UK
- Manchester Institute of Biotechnology
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27
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Maury J, Le Bailly BAF, Raftery J, Clayden J. Conformational cooperativity between helical domains of differing geometry in oligoamide–oligourea foldamer chimeras. Chem Commun (Camb) 2015; 51:11802-5. [DOI: 10.1039/c5cc02995c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Two foldamer domains of different classes (urea and amide) remain in conformational communication, and adopt a well-defined global structure in solution, provided the interdomain hydrogen-bonds are suitably orientated.
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Affiliation(s)
- Julien Maury
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
| | | | - James Raftery
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
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28
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Byrne L, Solà J, Clayden J. Screw sense alone can govern enantioselective extension of a helical peptide by kinetic resolution of a racemic amino acid. Chem Commun (Camb) 2015; 51:10965-8. [DOI: 10.1039/c5cc01790d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Helical secondary structure alone, even in the absence of local chiral residues, can direct the enantioselectivity of peptide coupling.
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Affiliation(s)
- Liam Byrne
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
| | - Jordi Solà
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
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29
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Pike SJ, Diemer V, Raftery J, Webb SJ, Clayden J. Designing foldamer-foldamer interactions in solution: the roles of helix length and terminus functionality in promoting the self-association of aminoisobutyric acid oligomers. Chemistry 2014; 20:15981-90. [PMID: 25280242 DOI: 10.1002/chem.201403626] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [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: 05/21/2014] [Indexed: 12/11/2022]
Abstract
The biological activity of antibiotic peptaibols has been linked to their ability to aggregate, but the structure-activity relationship for aggregation is not well understood. Herein, we report a systematic study of a class of synthetic helical oligomer (foldamer) composed of aminoisobutyric acid (Aib) residues, which mimic the folding behavior of peptaibols. NMR spectroscopic analysis was used to quantify the dimerization constants in solution, which showed hydrogen-bond donors at the N terminus promoted aggregation more effectively than similar modifications at the C terminus. Elongation of the peptide chain also favored aggregation. The geometry of aggregation in solution was investigated by means of titrations with [D6]DMSO and 2D NOE NMR spectroscopy, which allowed the NH protons most involved in intermolecular hydrogen bonds in solution to be identified. X-ray crystallography studies of two oligomers allowed a comparison of the inter- and intramolecular hydrogen-bonding interactions in the solid state and in solution and gave further insight into the geometry of foldamer-foldamer interactions. These solution-based and solid-state studies indicated that the preferred geometry for aggregation is through head-to-tail interactions between the N and C termini of adjacent Aib oligomers.
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Affiliation(s)
- Sarah J Pike
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL (UK), Fax: (+44) 161-275-4939
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30
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De Poli M, Byrne L, Brown RA, Solà J, Castellanos A, Boddaert T, Wechsel R, Beadle JD, Clayden J. Engineering the Structure of an N-Terminal β-Turn To Maximize Screw-Sense Preference in Achiral Helical Peptide Chains. J Org Chem 2014; 79:4659-75. [DOI: 10.1021/jo500714b] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Matteo De Poli
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Liam Byrne
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Robert A. Brown
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jordi Solà
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | | | - Thomas Boddaert
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Romina Wechsel
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jonathan D. Beadle
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jonathan Clayden
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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31
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Abstract
A single thionoglycine (glycine thioamide, -HNCH2C(=S)-) residue inserted into a peptide foldamer provides both a pair of germinal protons for use as a (1)H NMR stereochemical probe and a chromophore giving rise to a well defined Cotton effect in CD. Comparison of the response of these two features to a local helically chiral environment validates them as independent methods for quantifying the conformational screw-sense preference of a helical oligomer, in this case a peptide made of repeated Aib units. The sign of the Cotton effect provides a measure of the sign of the screw-sense preference, while both the chemical shift separation of the anisochronous signals of the glycine CH2 group and the magnitude of the Cotton effect give an estimate of the helicity excess of the oligomer. The thionoglycine unit is readily introduced synthetically by a thionation of a BocGlyAibOMe dipeptide.
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Affiliation(s)
- Matteo De Poli
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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32
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Orcel U, De Poli M, De Zotti M, Clayden J. The N-Terminal Nonapeptide of Cephaibols A and C: A Naturally Occurring Example of Mismatched Helical Screw-Sense Control. Chemistry 2013; 19:16357-65. [DOI: 10.1002/chem.201302648] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Indexed: 12/14/2022]
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