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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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2
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Martínez‐Crespo L, Vitórica‐Yrezábal IJ, Whitehead GFS, Webb SJ. Chemically Fueled Communication Along a Scaffolded Nanoscale Array of Squaramides. Angew Chem Int Ed Engl 2023; 62:e202307841. [PMID: 37429824 PMCID: PMC10952809 DOI: 10.1002/anie.202307841] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/12/2023]
Abstract
Relaying conformational change over several nanometers is central to the function of allosterically regulated proteins. Replicating this mechanism artificially would provide important communication tools, but requires nanometer-sized molecules that reversibly switch between defined shapes in response to signaling molecules. In this work, 1.8 nm long rigid rod oligo(phenylene-ethynylene)s are scaffolds for switchable multi-squaramide hydrogen-bond relays. Each relay can adopt either a parallel or an antiparallel orientation relative to the scaffold; the preferred orientation is dictated by a director group at one end. An amine director responded to proton signals, with acid-base cycles producing multiple reversible changes in relay orientation that were reported by a terminal NH, which is 1.8 nm distant. Moreover, a chemical fuel acted as a dissipative signal. As the fuel was consumed, the relay reverted to its original orientation, illustrating how information from out-of-equilibrium molecular signals can be communicated to a distant site.
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Affiliation(s)
- Luis Martínez‐Crespo
- Department of ChemistryUniversity of Manchester Oxford RoadManchesterM13 9PLUK
- Manchester Institute of BiotechnologyUniversity of Manchester131 Princess StreetManchesterM1 7DNUK
| | | | | | - Simon J. Webb
- Department of ChemistryUniversity of Manchester Oxford RoadManchesterM13 9PLUK
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3
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Al Nasser HA, Martinez-Crespo L, Webb SJ, Dryfe RAW. Electrochemical assessment of a tripodal thiourea-based anion receptor at the liquid|liquid interface. Phys Chem Chem Phys 2023. [PMID: 37382482 DOI: 10.1039/d3cp01431b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
Thiourea-based receptors for anions have been widely studied due to their ability to transport anions across phospholipid bilayers. The binding affinity of a tripodal thiourea-based receptor for anions was assessed at the aqueous|organic interface using electrochemical measurements. A 1 : 1 stoichiometry was determined for the complexation of most anions, with a higher stoichiometry found in the presence of excess Cl- and Br- anions. High stability constants were estimated for the formation of the complexes at the aqueous|1,2-dichlorobenzene (DCB) interface. When compared with an organic solvent of higher polarity, nitrobenzene (NB), the high stability constants observed in DCB are believed to be due to the less competitive environment of the less polar solvent. Protonation of the receptor at the bridgehead tertiary amine was also inferred from the potential-dependent voltammetric measurements that are not related to anion:receptor complexation. The inherent advantages of the electrochemical method with the use of low polarity solvents are expected to provide new insights into the binding and transport of newly-developed neutral receptors.
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Affiliation(s)
- Hussain A Al Nasser
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
- Henry Royce Institute for Advanced Materials, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Luis Martinez-Crespo
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
- Manchester Institute of Biotechnology, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Simon J Webb
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Robert A W Dryfe
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
- Henry Royce Institute for Advanced Materials, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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4
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Tilly DP, Heeb JP, Webb SJ, Clayden J. Switching imidazole reactivity by dynamic control of tautomer state in an allosteric foldamer. Nat Commun 2023; 14:2647. [PMID: 37156760 PMCID: PMC10167260 DOI: 10.1038/s41467-023-38339-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/26/2023] [Indexed: 05/10/2023] Open
Abstract
Molecular biology achieves control over complex reaction networks by means of molecular systems that translate a chemical input (such as ligand binding) into an orthogonal chemical output (such as acylation or phosphorylation). We present an artificial molecular translation device that converts a chemical input - the presence of chloride ions - into an unrelated chemical output: modulation of the reactivity of an imidazole moiety, both as a Brønsted base and as a nucleophile. The modulation of reactivity operates through the allosteric remote control of imidazole tautomer states. The reversible coordination of chloride to a urea binding site triggers a cascade of conformational changes in a chain of ethylene-bridged hydrogen-bonded ureas, switching the chain's global polarity, that in turn modulates the tautomeric equilibrium of a distal imidazole, and hence its reactivity. Switching reactivities of active sites by dynamically controlling their tautomer states is an untapped strategy for building functional molecular devices with allosteric enzyme-like properties.
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Affiliation(s)
- David P Tilly
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Jean-Paul Heeb
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Simon J Webb
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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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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Silva J, Spiess R, Marchesi A, Flitsch SL, Gough JE, Webb SJ. Enzymatic elaboration of oxime-linked glycoconjugates in solution and on liposomes. J Mater Chem B 2022; 10:5016-5027. [PMID: 35723603 PMCID: PMC9258907 DOI: 10.1039/d2tb00714b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxime formation is a convenient one-step method for ligating reducing sugars to surfaces, producing a mixture of closed ring α- and β-anomers along with open-chain (E)- and (Z)-isomers. Here we show that despite existing as a mixture of isomers, N-acetylglucosamine (GlcNAc) oximes can still be substrates for β(1,4)-galactosyltransferase (β4GalT1). β4GalT1 catalysed the galactosylation of GlcNAc oximes by a galactose donor (UDP-Gal) both in solution and in situ on the surface of liposomes, with conversions up to 60% in solution and ca. 15–20% at the liposome surface. It is proposed that the β-anomer is consumed preferentially but long reaction times allow this isomer to be replenished by equilibration from the remaining isomers. Adding further enzymes gave more complex oligosaccharides, with a combination of α-1,3-fucosyltransferase, β4GalT1 and the corresponding sugar donors providing Lewis X coated liposomes. However, sialylation using T. cruzi trans-sialidase and sialyllactose provided only very small amounts of sialyl Lewis X (sLex) capped lipid. These observations show that combining oxime formation with enzymatic elaboration will be a useful method for the high-throughput surface modification of drug delivery vehicles, such as liposomes, with cell-targeting oligosaccharides. Despite existing as a mixture of isomers, reducing sugar oximes can still be substrates for glycosyltransferases.![]()
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Affiliation(s)
- Joana Silva
- Department 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
| | - Reynard Spiess
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester M1 7DN, UK
| | - Andrea Marchesi
- Department 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
| | - Sabine L Flitsch
- Department 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
| | - Julie E Gough
- Department of Materials and Henry Royce Institute, The University of Manchester, Manchester M13 9PL, UK
| | - Simon J Webb
- Department 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
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7
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Lizio MG, Campana M, De Poli M, Jefferies DF, Cullen W, Andrushchenko V, Chmel NP, Bouř P, Khalid S, Clayden J, Blanch E, Rodger A, Webb SJ. Insight into the Mechanism of Action and Peptide-Membrane Interactions of Aib-Rich Peptides: Multitechnique Experimental and Theoretical Analysis. Chembiochem 2021; 22:1656-1667. [PMID: 33411956 PMCID: PMC8248331 DOI: 10.1002/cbic.202000834] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/06/2021] [Indexed: 12/16/2022]
Abstract
The increase in resistant bacterial strains necessitates the identification of new antimicrobial molecules. Antimicrobial peptides (AMPs) are an attractive option because of evidence that bacteria cannot easily develop resistance to AMPs. The peptaibols, a class of naturally occurring AMPs, have shown particular promise as antimicrobial drugs, but their development has been hindered by their mechanism of action not being clearly understood. To explore how peptaibols might interact with membranes, circular dichroism, vibrational circular dichroism, linear dichroism, Raman spectroscopy, Raman optical activity, neutron reflectivity and molecular dynamics simulations have been used to study a small library of peptaibol mimics, the Aib-rich peptides. All the peptides studied quickly partitioned and oriented in membranes, and we found evidence of chiral interactions between the phospholipids and membrane-embedded peptides. The protocols presented in this paper open new ground by showing how chiro-optical spectroscopies can throw light on the mechanism of action of AMPs.
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Affiliation(s)
| | - Mario Campana
- ISIS Neutron and Muon SourceRutherford Appleton Laboratory Harwell DidcotOxfordOX11 0QXUK
| | - Matteo De Poli
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | | | - William Cullen
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
- Manchester Institute of BiotechnologyUniversity of Manchester131 Princess St.ManchesterM1 7DNUK
| | - Valery Andrushchenko
- Institute of Organic Chemistry and BiochemistryAcademy of SciencesFlemingovo náměstí 216610Prague 6Czech Republic
| | - Nikola P. Chmel
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
| | - Petr Bouř
- Institute of Organic Chemistry and BiochemistryAcademy of SciencesFlemingovo náměstí 216610Prague 6Czech Republic
| | - Syma Khalid
- School of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
| | - Jonathan Clayden
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Ewan Blanch
- School of ScienceRMIT UniversityGPO Box 2476MelbourneVictoria3001Australia
| | - Alison Rodger
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
- Department of Molecular SciencesMacquarie UniversitySydneyNSW 2109Australia
| | - Simon J. Webb
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
- Manchester Institute of BiotechnologyUniversity of Manchester131 Princess St.ManchesterM1 7DNUK
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8
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Chivers PRA, Dookie RS, Gough JE, Webb SJ. Photo-dissociation of self-assembled (anthracene-2-carbonyl)amino acid hydrogels. Chem Commun (Camb) 2020; 56:13792-13795. [PMID: 33078185 DOI: 10.1039/d0cc05292b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Amino acids modified with an N-terminal anthracene group self-assemble into supramolecular hydrogels upon the addition of a range of salts or cell culture medium. Gel-phase photo-dimerisation of gelators results in hydrogel disassembly and was used to recover cells from 3D culture.
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Affiliation(s)
- Phillip R A Chivers
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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9
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August DP, Borsley S, Cockroft SL, Della Sala F, Leigh DA, Webb SJ. Transmembrane Ion Channels Formed by a Star of David [2]Catenane and a Molecular Pentafoil Knot. J Am Chem Soc 2020; 142:18859-18865. [PMID: 33084320 PMCID: PMC7745878 DOI: 10.1021/jacs.0c07977] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [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: 12/19/2022]
Abstract
A (FeII)6-coordinated triply interlocked ("Star of David") [2]catenane (612 link) and a (FeII)5-coordinated pentafoil (51) knot are found to selectively transport anions across phospholipid bilayers. Allostery, topology, and building block stoichiometry all play important roles in the efficacy of the ionophoric activity. Multiple FeII cation coordination by the interlocked molecules is crucial: the demetalated catenane exhibits no anion binding in solution nor any transmembrane ion transport properties. However, the topologically trivial, Lehn-type cyclic hexameric FeII helicates-which have similar anion binding affinities to the metalated Star of David catenane in solution-also display no ion transport properties. The unanticipated difference in behavior between the open- and closed-loop structures may arise from conformational restrictions in the linking groups that likely enhances the rigidity of the channel-forming topologically complex molecules. The (FeII)6-coordinated Star of David catenane, derived from a hexameric cyclic helicate, is 2 orders of magnitude more potent in terms of ion transport than the (FeII)5-coordinated pentafoil knot, derived from a cyclic pentamer of the same building block. The reduced efficacy is reminiscent of multisubunit protein ion channels assembled with incorrect monomer stoichiometries.
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Affiliation(s)
- David P August
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Stefan Borsley
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Scott L Cockroft
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Flavio Della Sala
- Department 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
| | - David A Leigh
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Simon J Webb
- Department 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
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10
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Jones EJH, Goodwin A, Orekhova E, Charman T, Dawson G, Webb SJ, Johnson MH. Infant EEG theta modulation predicts childhood intelligence. Sci Rep 2020; 10:11232. [PMID: 32641754 PMCID: PMC7343785 DOI: 10.1038/s41598-020-67687-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 06/04/2020] [Indexed: 11/08/2022] Open
Abstract
Intellectual functioning is a critical determinant of economic and personal productivity. Identifying early neural predictors of cognitive function in infancy will allow us to map the neurodevelopmental pathways that underpin individual differences in intellect. Here, in three different cohorts we investigate the association between a putative neurophysiological indicator of information encoding (change in frontal theta during a novel video) in infancy and later general cognitive outcome. In a discovery cohort of 12-month-old typically developing infants, we recorded EEG during presentation of dynamic movies of people and objects. Frontal theta power (3-6 Hz) significantly increased during the course of viewing each video. Critically, increase in frontal theta during viewing of a video was associated with a differential response to repetition of that specific video, confirming relation to learning. Further, individual differences in the magnitude of change in frontal theta power were related to concurrent nonverbal cognitive level. We then sought to extend this association in two independent samples enriched for variation in cognitive outcome due to the inclusion of infants at familial risk for autism. We observed similar patterns of theta EEG change at 12 months, and found a predictive relation to verbal and nonverbal cognitive skills measured at 2, 3 and 7 years of age. For the subset of high-risk infants later diagnosed with autism, infant theta EEG explained over 80% of the variance in nonverbal skills at age 3 years. We suggest that EEG theta change in infancy is an excellent candidate predictive biomarker that could yield substantial insight into the mechanisms that underlie individual differences in childhood intelligence, particularly in high risk populations.
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Affiliation(s)
- E J H Jones
- Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK.
| | - A Goodwin
- Institute of Psychiatry, King's College London, 16 De Crespigny Park, Camberwell, London, SE5 8AF, UK
| | - E Orekhova
- MedTech West and the Institute of Neuroscience and Physiology, Sahlgrenska Academ, The University of Gothenburg, Kungsgatan 12, SE 411 19, Gothenburg, Sweden
- MEG Centre, Moscow State University of Psychology and Education, 123290, Moscow, Russia
| | - T Charman
- Institute of Psychiatry, King's College London, 16 De Crespigny Park, Camberwell, London, SE5 8AF, UK
| | - G Dawson
- Duke Centre for Autism and Brain Development, Department of Psychiatry and Behavioral Sciences, Duke University, 4584 White Zone, Duke South, Durham, 27705, NC, USA
| | - S J Webb
- Center On Human Development and Disability, University of Washington, 1701 NE Columbia Rd, Seattle, WA, 98195, USA
- Department of Psychiatry & Behavioral Science, University of Washington, 2815 Eastlake Ave E, Seattle, WA, 98102, USA
- Center On Child Behavior and Development, Seattle Children's Research Institute, 2001 Eighth Ave, Suite 400, Seattle, WA, 98121, USA
| | - M H Johnson
- Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK
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11
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Peters AD, Borsley S, Della Sala F, Cairns-Gibson DF, Leonidou M, Clayden J, Whitehead GFS, Vitórica-Yrezábal IJ, Takano E, Burthem J, Cockroft SL, Webb SJ. Switchable foldamer ion channels with antibacterial activity. Chem Sci 2020; 11:7023-7030. [PMID: 32953034 PMCID: PMC7481839 DOI: 10.1039/d0sc02393k] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [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: 04/27/2020] [Accepted: 06/04/2020] [Indexed: 12/19/2022] Open
Abstract
Synthetic ion channels may have applications in treating channelopathies and as new classes of antibiotics, particularly if ion flow through the channels can be controlled. Here we describe triazole-capped octameric α-aminoisobutyric acid (Aib) foldamers that "switch on" ion channel activity in phospholipid bilayers upon copper(ii) chloride addition; activity is "switched off" upon copper(ii) extraction. X-ray crystallography showed that CuCl2 complexation gave chloro-bridged foldamer dimers, with hydrogen bonds between dimers producing channels within the crystal structure. These interactions suggest a pathway for foldamer self-assembly into membrane ion channels. The copper(ii)-foldamer complexes showed antibacterial activity against B. megaterium strain DSM319 that was similar to the peptaibol antibiotic alamethicin, but with 90% lower hemolytic activity.
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Affiliation(s)
- Anna D Peters
- Department 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
| | - Stefan Borsley
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK
| | - Flavio Della Sala
- Department 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
| | - Dominic F Cairns-Gibson
- EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK
| | - Marios Leonidou
- Department 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
| | - George F S Whitehead
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | | | - Eriko Takano
- Department 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
| | - John Burthem
- Department of Haematology , Manchester Royal Infirmary , Manchester University NHS Foundation Trust , Manchester M13 9WL , UK.,Division of Cancer Sciences , School of Medical Sciences , University of Manchester , Manchester , UK
| | - Scott L Cockroft
- EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK
| | - Simon J Webb
- Department 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
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12
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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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13
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Fallows TW, McGrath AJ, Silva J, McAdams SG, Marchesi A, Tuna F, Flitsch SL, Tilley RD, Webb SJ. High-throughput chemical and chemoenzymatic approaches to saccharide-coated magnetic nanoparticles for MRI. Nanoscale Adv 2019; 1:3597-3606. [PMID: 36133529 PMCID: PMC9417132 DOI: 10.1039/c9na00376b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/29/2019] [Indexed: 05/28/2023]
Abstract
There is a need for biofunctionalised magnetic nanoparticles for many biomedical applications, including MRI contrast agents that have a range of surface properties and functional groups. A library of eleven adducts, each formed by condensing a reducing sugar with a catechol hydrazide, for nanoparticle functionalisation has been created using a high-throughput chemical synthesis methodology. The enzymatic transformation of an N-acetylglucosamine (GlcNAc) adduct into an N-acetyllactosamine adduct by β-1,4-galactosyltransferase illustrates how chemoenzymatic methods could provide adducts bearing complex and expensive glycans. Superparamagnetic iron oxide nanoparticles (8 nm diameter, characterised by TEM, DLS and SQUID) were coated with these adducts and the magnetic resonance imaging (MRI) properties of GlcNAc-labelled nanoparticles were determined. This straightforward approach can produce a range of MRI contrast agents with a variety of biofunctionalised surfaces.
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Affiliation(s)
- Thomas W Fallows
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- Manchester Institute of Biotechnology, University of Manchester 131 Princess St Manchester M1 7DN UK
| | - Andrew J McGrath
- School of Chemistry, University of New South Wales Australia
- Australian Centre for NanoMedicine, University of New South Wales Australia
| | - Joana Silva
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- Manchester Institute of Biotechnology, University of Manchester 131 Princess St Manchester M1 7DN UK
| | - Simon G McAdams
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- School of Materials, University of Manchester Oxford Road Manchester UK
| | - Andrea Marchesi
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- Manchester Institute of Biotechnology, University of Manchester 131 Princess St Manchester M1 7DN UK
| | - Floriana Tuna
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- Photon Science Institute, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Sabine L Flitsch
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- Manchester Institute of Biotechnology, University of Manchester 131 Princess St Manchester M1 7DN UK
| | - Richard D Tilley
- School of Chemistry, University of New South Wales Australia
- Australian Centre for NanoMedicine, University of New South Wales Australia
- Electron Microscope Unit, Mark Wainwright Analytical Centre, University of New South Wales Australia
| | - Simon J Webb
- School of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK +44 (0)161 306 4524
- Manchester Institute of Biotechnology, University of Manchester 131 Princess St Manchester M1 7DN UK
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14
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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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15
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Cummings M, Peters AD, Whitehead GFS, Menon BRK, Micklefield J, Webb SJ, Takano E. Assembling a plug-and-play production line for combinatorial biosynthesis of aromatic polyketides in Escherichia coli. PLoS Biol 2019; 17:e3000347. [PMID: 31318855 PMCID: PMC6638757 DOI: 10.1371/journal.pbio.3000347] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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: 02/04/2019] [Accepted: 06/14/2019] [Indexed: 11/19/2022] Open
Abstract
Polyketides are a class of specialised metabolites synthesised by both eukaryotes and prokaryotes. These chemically and structurally diverse molecules are heavily used in the clinic and include frontline antimicrobial and anticancer drugs such as erythromycin and doxorubicin. To replenish the clinicians' diminishing arsenal of bioactive molecules, a promising strategy aims at transferring polyketide biosynthetic pathways from their native producers into the biotechnologically desirable host Escherichia coli. This approach has been successful for type I modular polyketide synthases (PKSs); however, despite more than 3 decades of research, the large and important group of type II PKSs has until now been elusive in E. coli. Here, we report on a versatile polyketide biosynthesis pipeline, based on identification of E. coli-compatible type II PKSs. We successfully express 5 ketosynthase (KS) and chain length factor (CLF) pairs-e.g., from Photorhabdus luminescens TT01, Streptomyces resistomycificus, Streptoccocus sp. GMD2S, Pseudoalteromonas luteoviolacea, and Ktedonobacter racemifer-as soluble heterodimeric recombinant proteins in E. coli for the first time. We define the anthraquinone minimal PKS components and utilise this biosynthetic system to synthesise anthraquinones, dianthrones, and benzoisochromanequinones (BIQs). Furthermore, we demonstrate the tolerance and promiscuity of the anthraquinone heterologous biosynthetic pathway in E. coli to act as genetically applicable plug-and-play scaffold, showing it to function successfully when combined with enzymes from phylogenetically distant species, endophytic fungi and plants, which resulted in 2 new-to-nature compounds, neomedicamycin and neochaetomycin. This work enables plug-and-play combinatorial biosynthesis of aromatic polyketides using bacterial type II PKSs in E. coli, providing full access to its many advantages in terms of easy and fast genetic manipulation, accessibility for high-throughput robotics, and convenient biotechnological scale-up. Using the synthetic and systems biology toolbox, this plug-and-play biosynthetic platform can serve as an engine for the production of new and diversified bioactive polyketides in an automated, rapid, and versatile fashion.
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Affiliation(s)
- Matthew Cummings
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Anna D. Peters
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - George F. S. Whitehead
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Binuraj R. K. Menon
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
- Warwick Integrative Synthetic Biology Centre, WISB, School of Life Sciences, The University of Warwick, Coventry, United Kingdom
| | - Jason Micklefield
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Simon J. Webb
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Eriko Takano
- Manchester Synthetic Biology Research Centre SYNBIOCHEM, Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, United Kingdom
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16
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Peters AD, McCallion C, Booth A, Adams JA, Rees-Unwin K, Pluen A, Burthem J, Webb SJ. Synthesis and biological activity of a CXCR4-targeting bis(cyclam) lipid. Org Biomol Chem 2019; 16:6479-6490. [PMID: 30155533 DOI: 10.1039/c8ob01439f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A bis(cyclam)-capped cholesterol lipid designed to bind C-X-C chemokine receptor type 4 (CXCR4) was synthesised in good overall yield from 4-methoxyphenol through a seven step synthetic route, which also provided a bis(cyclam) intermediate bearing an octaethyleneglycol-primary amine that can be easily derivatised. This bis(cyclam)-capped cholesterol lipid was water soluble and self-assembled into micellar and non-micellar aggregates in water at concentrations above 8 μM. The bioactivity of the bis(cyclam)-capped cholesterol lipid was assessed using primary chronic lymphocytic leukaemia (CLL) cells, first with a competition binding assay then with a chemotaxis assay along a C-X-C motif chemokine ligand 12 (CXCL12) concentration gradient. At 20 μM, the bis(cyclam)-capped cholesterol lipid was as effective as the commercial drug AMD3100 for preventing the migration of CLL cells, despite a lower affinity for CXCR4 than AMD3100.
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Affiliation(s)
- Anna D Peters
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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17
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Chapman NH, Bernier RA, Webb SJ, Munson J, Blue EM, Chen DH, Heigham E, Raskind WH, Wijsman EM. Replication of a rare risk haplotype on 1p36.33 for autism spectrum disorder. Hum Genet 2018; 137:807-815. [PMID: 30276537 PMCID: PMC6309233 DOI: 10.1007/s00439-018-1939-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/22/2018] [Indexed: 01/15/2023]
Abstract
Hundreds of genes have been implicated in autism spectrum disorders (ASDs). In genetically heterogeneous conditions, large families with multiple affected individuals provide strong evidence implicating a rare variant, and replication of the same variant in multiple families is unusual. We previously published linkage analyses and follow-up exome sequencing in seven large families with ASDs, implicating 14 rare exome variants. These included rs200195897, which was transmitted to four affected individuals in one family. We attempted replication of those variants in the MSSNG database. MSSNG is a unique resource for replication of ASD risk loci, containing whole genome sequence (WGS) on thousands of individuals diagnosed with ASDs and family members. For each exome variant, we obtained all carriers and their relatives in MSSNG, using a TDT test to quantify evidence for transmission and association. We replicated the transmission of rs200195897 to four affected individuals in three additional families. rs200195897 was also present in three singleton affected individuals, and no unaffected individuals other than transmitting parents. We identified two additional rare variants (rs566472488 and rs185038034) transmitted with rs200195897 on 1p36.33. Sanger sequencing confirmed the presence of these variants in the original family segregating rs200195897. To our knowledge, this is the first example of a rare haplotype being transmitted with ASD in multiple families. The candidate risk variants include a missense mutation in SAMD11, an intronic variant in NOC2L, and a regulatory region variant close to both genes. NOC2L is a transcription repressor, and several genes involved in transcription regulation have been previously associated with ASDs.
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Affiliation(s)
- N H Chapman
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 359460, Seattle, WA, 98195, USA
| | - R A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA
- Center on Human Development and Disability, University of Washington, Seattle, WA, 98195, USA
| | - S J Webb
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA
- Center on Human Development and Disability, University of Washington, Seattle, WA, 98195, USA
| | - J Munson
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA
- Center on Human Development and Disability, University of Washington, Seattle, WA, 98195, USA
| | - E M Blue
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 359460, Seattle, WA, 98195, USA
| | - D-H Chen
- Department of Neurology, University of Washington, Seattle, WA, 98195, USA
| | - E Heigham
- Department of Neurology, University of Washington, Seattle, WA, 98195, USA
| | - W H Raskind
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 359460, Seattle, WA, 98195, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Ellen M Wijsman
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 359460, Seattle, WA, 98195, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA.
- Department of Biostatistics, University of Washington, Seattle, WA, 98195, USA.
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18
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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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19
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Lizio MG, Andrushchenko V, Pike SJ, Peters AD, Whitehead GFS, Vitórica-Yrezábal IJ, Mutter ST, Clayden J, Bouř P, Blanch EW, Webb SJ. Optically Active Vibrational Spectroscopy of α-Aminoisobutyric Acid Foldamers in Organic Solvents and Phospholipid Bilayers. Chemistry 2018; 24:9399-9408. [PMID: 29745985 DOI: 10.1002/chem.201801121] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 03/05/2018] [Indexed: 12/12/2022]
Abstract
Helical α-aminoisobutyric acid (Aib) foldamers show great potential as devices for the communication of conformational information across phospholipid bilayers, but determining their conformation in bilayers remains a challenge. In the present study, Raman, Raman optical activity (ROA), infrared (IR) and vibrational circular dichroism (VCD) spectroscopies have been used to analyze the conformational preferences of Aib foldamers in solution and when interacting with bilayers. A 310 -helix marker band at 1665-1668 cm-1 in Raman spectra was used to show that net helical content increased strongly with oligomer length. ROA and VCD spectra of chiral Aib foldamers provided the chiroptical signature for both left- and right-handed 310 -helices in organic solvents, with VCD establishing that foldamer screw-sense was preserved when the foldamers became embedded within bilayers. However, the population distribution between different secondary structures was perturbed by the chiral phospholipid. These studies indicate that ROA and VCD spectroscopies are valuable tools for the study of biomimetic structures, such as artificial signal transduction molecules, in phospholipid bilayers.
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Affiliation(s)
- Maria Giovanna Lizio
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Valery Andrushchenko
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610, Prague 6, Czech Republic
| | - Sarah J Pike
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.,Faculty of Life Sciences, University of Bradford, Bradford, West Yorkshire, BD7 1DP, UK
| | - Anna D Peters
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,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
| | | | - Shaun T Mutter
- 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
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610, Prague 6, Czech Republic
| | - Ewan W Blanch
- School of Science, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Simon J Webb
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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20
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Adam C, Peters AD, Lizio MG, Whitehead GFS, Diemer V, Cooper JA, Cockroft SL, Clayden J, Webb SJ. The Role of Terminal Functionality in the Membrane and Antibacterial Activity of Peptaibol-Mimetic Aib Foldamers. Chemistry 2018; 24:2249-2256. [PMID: 29210477 DOI: 10.1002/chem.201705299] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [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: 11/08/2017] [Indexed: 01/04/2023]
Abstract
Peptaibols are peptide antibiotics that typically feature an N-terminal acetyl cap, a C-terminal aminoalcohol, and a high proportion of α-aminoisobutyric acid (Aib) residues. To establish how each feature might affect the membrane-activity of peptaibols, biomimetic Aib foldamers with different lengths and terminal groups were synthesised. Vesicle assays showed that long foldamers (eleven Aib residues) with hydrophobic termini had the highest ionophoric activity. C-terminal acids or primary amides inhibited activity, while replacement of an N-terminal acetyl with an azide group made little difference. Crystallography showed that N3 Aib11 CH2 OTIPS folded into a 310 helix 2.91 nm long, which is close to the bilayer hydrophobic width. Planar bilayer conductance assays showed discrete ion channels only for N-acetylated foldamers. However long foldamers with hydrophobic termini had the highest antibacterial activity, indicating that ionophoric activity in vesicles was a better indicator of antibacterial activity than the observation of discrete ion channels.
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Affiliation(s)
- Catherine Adam
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Anna D Peters
- 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
| | - 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
| | - George F S Whitehead
- 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.,Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester, M1 7DN, UK
| | - James A Cooper
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Scott L Cockroft
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, 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.,Manchester Institute of Biotechnology, University of Manchester, 131 Princess St, Manchester, M1 7DN, UK
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21
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Jones EJH, Dawson G, Webb SJ. Sensory hypersensitivity predicts enhanced attention capture by faces in the early development of ASD. Dev Cogn Neurosci 2018; 29:11-20. [PMID: 28457745 PMCID: PMC5638681 DOI: 10.1016/j.dcn.2017.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 01/04/2017] [Accepted: 04/03/2017] [Indexed: 11/29/2022] Open
Abstract
Sensory sensitivity is prevalent among young children with ASD, but its relation to social communication impairment is unclear. Recently, increased sensory hypersensitivity has been linked to greater activity of the neural salience network (Green et al., 2016). Increased neural sensitivity to stimuli, especially social stimuli, could provide greater opportunity for social learning and improved outcomes. Consistent with this framework, in Experiment 1 we found that parent report of greater sensory hypersensitivity at 2 years in toddlers with ASD (N=27) was predictive of increased neural responsiveness to social stimuli (larger amplitude event-related potential/ERP responses to faces at P1, P400 and Nc) at 4 years, and this in turn was related to parent report of increased social approach at 4 years. In Experiment 2, parent report of increased perceptual sensitivity at 6 months in infants at low and high familial risk for ASD (N=35) predicted larger ERP P1 amplitude to faces at 18 months. Increased sensory hypersensitivity in early development thus predicted greater attention capture by faces in later development, and this related to more optimal social behavioral development. Sensory hypersensitivity may index a child's ability to benefit from supportive environments during development. Early sensory symptoms may not always be developmentally problematic for individuals with ASD.
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Affiliation(s)
- E J H Jones
- Centre for Brain and Cognitive Development, Department of Psychological Sciences, Birkbeck College, University of London, UK.
| | - G Dawson
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States; Duke Center for Autism and Brain Development, Duke University, Durham, NC, United States; Duke Institute for Brain Sciences, Durham, NC, United States
| | - S J Webb
- Center on Human Development and Disability, University of Washington, Seattle, WA, United States; Department of Psychiatry & Behavioral Science, University of Washington, Seattle, WA, United States; Center on Child Behavior and Development, Seattle Children's Research Institute, Seattle, WA, United States
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22
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Craven FL, Silva J, Segarra-Maset MD, Huang K, Both P, Gough JE, Flitsch SL, Webb SJ. ‘One-pot’ sequential enzymatic modification of synthetic glycolipids in vesicle membranes. Chem Commun (Camb) 2018; 54:1347-1350. [DOI: 10.1039/c7cc09148f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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
To create vesicles with cell-targeting coatings, two soluble enzymes were used to directly glycosylate vesicle surfaces in a ‘one-pot’ procedure.
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Affiliation(s)
- Faye L. Craven
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
| | - Joana Silva
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
| | - Maria D. Segarra-Maset
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
| | - Kun Huang
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
| | - Peter Both
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
| | - Julie E. Gough
- School of Materials
- University of Manchester
- MSS Tower
- Manchester M13 9PL
- UK
| | - Sabine L. Flitsch
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
| | - Simon J. Webb
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
- Manchester Institute of Biotechnology
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23
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Li W, McManus D, Liu H, Casiraghi C, Webb SJ. Aqueous dispersions of nanostructures formed through the self-assembly of iminolipids with exchangeable hydrophobic termini. Phys Chem Chem Phys 2017. [PMID: 28642943 DOI: 10.1039/c7cp02868g] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The addition of amines to an aldehyde surfactant, which was designed to be analogous to didodecyldimethylammonium bromide, gave exchangeable "iminolipids" that self-assembled to give stable aqueous dispersions of nano-sized vesicles. For example, sonication of suspensions of the n-hexylamine-derived iminolipid gave vesicles 50 to 200 nm in diameter that could encapsulate a water-soluble dye. The iminolipids could undergo dynamic exchange with added amines, and the resulting equilibrium constants (Krel) were quantified by 1H NMR spectroscopy. In the absence of lipid self-assembly, in CDCl3, the assayed primary amines gave very similar Krel values. However in D2O the value of Krel generally increased with increasing amine hydrophobicity, consistent with partitioning into a self-assembled bilayer. Amines with aromatic groups showed significantly higher values of Krel in D2O compared to similarly hydrophobic alkylamines, suggesting that π-π interactions favor lipid self-assembly. Given this synergistic relationship, π-rich pyrenyliminolipids were created and used to exfoliate graphite, leading to aqueous dispersions of graphene flakes that were stable over several months.
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Affiliation(s)
- Wen Li
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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24
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Affiliation(s)
- Michael A. Hollas
- Department of Chemistry; Photon Science Institute; University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Simon J. Webb
- Department of Chemistry; Manchester Institute of Biotechnology; University of Manchester; 131 Princess Street Manchester M1 7DN UK
| | - Sabine L. Flitsch
- Department of Chemistry; Manchester Institute of Biotechnology; University of Manchester; 131 Princess Street Manchester M1 7DN UK
| | - Alistair J. Fielding
- Department of Chemistry; Photon Science Institute; University of Manchester; Oxford Road Manchester M13 9PL UK
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25
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Hollas MA, Webb SJ, Flitsch SL, Fielding AJ. A Bifunctional Spin Label for Ligand Recognition on Surfaces. Angew Chem Int Ed Engl 2017; 56:9449-9453. [PMID: 28570782 PMCID: PMC5577508 DOI: 10.1002/anie.201703929] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 04/16/2017] [Revised: 05/22/2017] [Indexed: 01/21/2023]
Abstract
In situ monitoring of biomolecular recognition, especially at surfaces, still presents a significant technical challenge. Electron paramagnetic resonance (EPR) of biomolecules spin-labeled with nitroxides can offer uniquely sensitive and selective insights into these processes, but new spin-labeling strategies are needed. The synthesis and study of a bromoacrylaldehyde spin label (BASL), which features two attachment points with orthogonal reactivity is reported. The first examples of mannose and biotin ligands coupled to aqueous carboxy-functionalized gold nanoparticles through a spin label are presented. EPR spectra were obtained for the spin-labeled ligands both free in solution and attached to nanoparticles. The labels were recognized by the mannose-binding lectin, Con A, and the biotin-binding protein avidin-peroxidase. Binding gave quantifiable changes in the EPR spectra from which binding profiles could be obtained that reflect the strength of binding in each case.
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Affiliation(s)
- Michael A Hollas
- Department of Chemistry, Photon Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Simon J Webb
- Department of Chemistry, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Sabine L Flitsch
- Department of Chemistry, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Alistair J Fielding
- Department of Chemistry, Photon Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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26
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Navot N, Jorgenson AG, Webb SJ. Maternal experience raising girls with autism spectrum disorder: a qualitative study. Child Care Health Dev 2017; 43:536-545. [PMID: 28464352 PMCID: PMC5993544 DOI: 10.1111/cch.12470] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 03/23/2017] [Accepted: 04/03/2017] [Indexed: 01/03/2023]
Abstract
BACKGROUND A growing line of research has sought to characterize the different presentations of autism spectrum disorder (ASD) among boys and girls. Much less is known about maternal experience and mother-child relationship in children with ASD based on child gender. The present qualitative study aimed to investigate the mother-daughter relationship from the perspective of mothers who are raising girls with ASD with normal intelligence and functional verbal communication. METHODS Eleven in-depth interviews were conducted with mothers of girls with ASD, ages 10-19 years. Data were analysed in an interactive process commonly used in naturalistic inquiry. Results provide insight into the unique maternal experience of raising a daughter with ASD. RESULTS Mothers reported a sense of exclusion from the neurotypical population and male-dominant ASD population and transformation in relationship. Themes identified were skepticism and delayed diagnosis, disbelief from others, lack of information about girls with ASD, higher social demands in adolescence, puberty challenges around hygiene, disappointment about physical appearance, vulnerability in relationships and worries about future functioning. The mother-daughter relationship started with an early expectation of a close and intimate relationship that then underwent a transformation, which challenged maternal competence, reshaped expectations and created a different bond between mother and daughter. CONCLUSIONS The findings in this qualitative study highlight the impact of gender on the maternal experience of raising a daughter with ASD and contribute to a better understanding of the needs of both mothers and daughters. These results can help providers support the mother-daughter dyad by recognizing gender-specific challenges.
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Affiliation(s)
- N Navot
- Department of Child and Adolescent Psychiatry, Ziv Medical Center, Safed, Israel
- Department of Psychiatry and Behavioral Medicine, University of Washington, Seattle, WA, USA
| | - A G Jorgenson
- Department of Psychiatry and Behavioral Medicine, University of Washington, Seattle, WA, USA
| | - S J Webb
- Department of Psychiatry and Behavioral Medicine, University of Washington, Seattle, WA, USA
- Department of Epidemiology, University of Washington, Seattle, WA, USA
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27
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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28
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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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29
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Coxon TP, Fallows TW, Gough JE, Webb SJ. A versatile approach towards multivalent saccharide displays on magnetic nanoparticles and phospholipid vesicles. Org Biomol Chem 2016; 13:10751-61. [PMID: 26360423 DOI: 10.1039/c5ob01591j] [Citation(s) in RCA: 13] [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: 01/04/2023]
Abstract
A simple synthetic route has been devised for the production of coating agents that can give multivalent displays of saccharides on the surface of magnetite nanoparticles and phospholipid vesicles. A versatile and potentially high-throughput condensation reaction allowed the rapid synthesis of a variety of glycosylhydrazide conjugates with lipid, resorcinol or catechol termini, each in good yield and high anomeric purity. The hydrolytic stability of these adducts was assessed in D2O at different pD values using (1)H-NMR spectroscopy, whilst quartz crystal microbalance with dissipation monitoring (QCM-D) confirmed that the saccharide functionality on bilayers and on nanoparticles was still available to lectins. These multivalent saccharide displays promoted nanoparticle interactions with cells, for example N-acetylglucosamine-coated nanoparticles interacted much more effectively with 3T3 fibroblasts than uncoated nanoparticles with these cells. Despite potential sensitivity to oxidation, catechol coatings on magnetite nanoparticles were found to be more stable and generate better nanoparticle interactions with fibroblasts than resorcinol coatings.
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Affiliation(s)
- Thomas P Coxon
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK. and School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Thomas W Fallows
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK. and School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Julie E Gough
- School of Materials, University of Manchester, MSS Tower, M13 9PL, Manchester, UK.
| | - Simon J Webb
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK. and School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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30
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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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31
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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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32
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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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33
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Jones EJH, Venema K, Earl R, Lowy R, Barnes K, Estes A, Dawson G, Webb SJ. Reduced engagement with social stimuli in 6-month-old infants with later autism spectrum disorder: a longitudinal prospective study of infants at high familial risk. J Neurodev Disord 2016; 8:7. [PMID: 26981158 PMCID: PMC4791854 DOI: 10.1186/s11689-016-9139-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 02/17/2016] [Indexed: 11/18/2022] Open
Abstract
Background Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects more than 1 % of the population and close to 20 % of prospectively studied infants with an older sibling with ASD. Although significant progress has been made in characterizing the emergence of behavioral symptoms of ASD, far less is known about the underlying disruptions to early learning. Recent models suggest that core aspects of the causal path to ASD may only be apparent in early infancy. Here, we investigated social attention in 6- and 12-month-old infants who did and did not meet criteria for ASD at 24 months using both cognitive and electrophysiological methods. We hypothesized that a reduction in attention engagement to faces would be associated with later ASD. Methods In a prospective longitudinal design, we used measures of both visual attention (habituation) and brain function (event-related potentials to faces and objects) at 6 and 12 months and investigated the relationship to ASD outcome at 24 months. Results High-risk infants who met criteria for ASD at 24 months showed shorter epochs of visual attention, faster but less prolonged neural activation to faces, and delayed sensitization responses (increases in looking) to faces at 6 months; these differences were less apparent at 12 months. These findings are consistent with disrupted engagement of sustained attention to social stimuli. Conclusions These findings suggest that there may be fundamental early disruptions to attention engagement that may have cascading consequences for later social functioning. Electronic supplementary material The online version of this article (doi:10.1186/s11689-016-9139-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- E J H Jones
- Centre for Brain and Cognitive Development, Birkbeck College, University of London, London, UK
| | - K Venema
- Center on Human Development and Disability, University of Washington, Seattle, WA USA
| | - R Earl
- Center on Human Development and Disability, University of Washington, Seattle, WA USA
| | - R Lowy
- Center on Human Development and Disability, University of Washington, Seattle, WA USA ; Department of Speech and Hearing Sciences, University of Washington, Seattle, WA USA
| | - K Barnes
- Center for Child Health, Behavior and Development, Seattle Children's Hospital, Seattle, WA USA
| | - A Estes
- Center on Human Development and Disability, University of Washington, Seattle, WA USA ; Department of Speech and Hearing Sciences, University of Washington, Seattle, WA USA
| | - G Dawson
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC USA
| | - S J Webb
- Center on Human Development and Disability, University of Washington, Seattle, WA USA ; Center for Child Health, Behavior and Development, Seattle Children's Hospital, Seattle, WA USA ; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
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34
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King PJS, Giovanna Lizio M, Booth A, Collins RF, Gough JE, Miller AF, Webb SJ. A modular self-assembly approach to functionalised β-sheet peptide hydrogel biomaterials. Soft Matter 2016; 12:1915-1923. [PMID: 26702608 DOI: 10.1039/c5sm02039e] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Two complementary β-sheet-forming decapeptides have been created that form binary self-repairing hydrogels upon combination of the respective free-flowing peptide solutions at pH 7 and >0.28 wt%. The component peptides showed little structure separately but formed extended β-sheet fibres upon mixing, which became entangled to produce stiff hydrogels. Microscopy revealed two major structures; thin fibrils with a twisted or helical appearance and with widths comparable to the predicted lengths of the peptides within a β-sheet, and thicker, longer, interwoven fibres that appear to comprise laterally-packed fibrils. A range of gel stiffnesses (G' from 0.05 to 100 kPa) could be attained in this system by altering the assembly conditions, stiffnesses that cover the rheological properties desirable for cell culture scaffolds. Doping in a RGD-tagged component peptide at 5 mol% improved 3T3 fibroblast attachment and viability compared to hydrogel fibres without RGD functionalisation.
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Affiliation(s)
- Patrick J S King
- School of Chemistry, The University of Manchester, Brunswick Street, Manchester, M13 9PL, UK
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35
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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
![]()
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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36
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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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37
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Booth A, Pintre IC, Lin Y, Gough JE, Webb SJ. Release of proteins and enzymes from vesicular compartments by alternating magnetic fields. Phys Chem Chem Phys 2015; 17:15579-88. [PMID: 25785572 DOI: 10.1039/c4cp05872k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The magnetic release of catalytically active enzymes from vesicular compartments within aggregated nanomaterials has been demonstrated. These nanomaterials, magnetic nanoparticle-vesicle aggregates (MNPVs), were formed by the self-assembly of biotinylated silica-coated Fe3O4 nanoparticles, biotinylated vesicles and tetrameric avidin. The unique features of nanoscale magnetite allow adhesion between membranes to be combined with magnetically triggered transit of reagents across membranes. Adding short spacers between the adhesive biotin groups and the nanoparticle or vesicle surfaces was found to strengthen binding to avidin, with binding of avidin to biotinylated bilayers and biotinylated nanoparticles monitored by quartz crystal microgravimetry with dissipation (QCM-D). Three different reagents were released from the vesicle compartments of MNPVs by a pulse of alternating magnetic field, with the release of a dye modelling the release of small molecule substrates, and the release of cytochrome c modelling the release of biological polymers, such as enzymes. To confirm that enzymes could be released and maintain activity, trypsin was encapsulated and shown to digest casein after magnetically triggered release.
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Affiliation(s)
- Andrew Booth
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
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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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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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40
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Booth A, Coxon TP, Gough JE, Webb SJ. Targeting of a magnetic bionanomaterial to HepG2 human hepatocellular carcinoma cells using a galactose terminated lipid. ACTA ACUST UNITED AC 2014. [DOI: 10.1557/opl.2014.517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
ABSTRACTMagnetic nanoparticle-vesicle aggregates (MNPVs), a controlled release nanostructure, have been enhanced with the inclusion of a novel galactose terminated lipid for cell targeting. Quartz crystal microgravimetry with dissipation (QCM-D) demonstrated that the galactose headgroup was available to bind Erythrina Crista-galli lectin (ECL) when the lipid was incorporated into a lipid bilayer. Similarly, UV-visible spectrophotometry indicated that ECL recognized the galactose headgroup in vesicles, leading to vesicle adhesion and aggregation. Finally, confocal fluorescence microscopy was used to assess the galactose-mediated interaction of both vesicles and MNPVs with HepG2 human hepatocellular carcinoma cells expressing the asialoglycoprotein (ASGPR) galactose receptor.
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Abstract
Wulff-type boronic acids have been shown to act as ionophores at pH 8.2 by transporting Na(+) through phospholipid bilayers. A cholate-boronic acid conjugate was synthesised and shown to be an ionophore, although the hydroxyl-lined face of the cholate moiety did not enhance ion transport. Mechanistic studies suggested a carrier mechanism for Na(+) transport. The addition of fructose (>5 mM) strongly inhibited ionophoric activity of the cholate-boronic acid conjugate, mirrored by a strong decrease in the ability of this compound to partition into an organic phase. Modelling of the partitioning and ion transport data, using a fructose/boronic acid binding constant measured at pH 8.2, showed a good correlation with the extent of fructose/boronic acid complexation and suggested high polarity fructose/boronic acid complexes are poor ionophores. The sensitivity of ion transport to fructose implies that boronic acid-based antibiotic ionophores with activity modulated by polysaccharides in the surrounding environment may be accessible.
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Affiliation(s)
- James R D Brown
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, University of Manchester, 131 Princess St., Manchester M1 7DN, UK.
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Noble GT, Craven FL, Segarra-Maset MD, Martínez JER, Šardzík R, Flitsch SL, Webb SJ. Sialylation of lactosyl lipids in membrane microdomains byT. cruzi trans-sialidase. Org Biomol Chem 2014; 12:9272-8. [DOI: 10.1039/c4ob01852d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SolubleT. cruzi trans-sialidase transformed a synthetic lactosyl glycolipid in microdomains more slowly than the same substrate dispersed across the bilayer surface, producing phospholipid vesicles with a Neu5Ac(α2-3)Gal(β1-4)Glc “glycocalyx”.
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Affiliation(s)
- Gavin T. Noble
- Manchester Institute of Biotechnology and School of Chemistry
- The University of Manchester
- Manchester, UK
| | - Faye L. Craven
- Manchester Institute of Biotechnology and School of Chemistry
- The University of Manchester
- Manchester, UK
| | | | | | - Robert Šardzík
- Manchester Institute of Biotechnology and School of Chemistry
- The University of Manchester
- Manchester, UK
| | - Sabine L. Flitsch
- Manchester Institute of Biotechnology and School of Chemistry
- The University of Manchester
- Manchester, UK
| | - Simon J. Webb
- Manchester Institute of Biotechnology and School of Chemistry
- The University of Manchester
- Manchester, UK
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Abstract
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Cells carefully control the transit of compounds through their membranes using “gated” protein channels that respond to chemical stimuli. Connexin gap junctions, which are high conductance cell-to-cell channels, are a remarkable class of “gated” channel with multiple levels of assembly. A gap junction between adhering cells comprises two half-channels in each cell membrane that adhere to each other to form a continuous cell-to-cell channel. Each half-channel is a hexameric assembly of six protein transmembrane subunits. These gap junctions display both intramembrane assembly and intermembrane assembly, making them an attractive target for biomimetic studies. Although many examples of self-assembled channels have been developed, few can also mediate intermembrane adhesion. Developing systems that combine membrane adhesion with controlled transit across the membrane would not only provide a better understanding of self-assembly in and around the membrane, but would also provide a route towards smart biomaterials, targeted drug delivery and an interface with nanotechnology. This Account describes our biomimetic approaches to combining membrane adhesion with membrane transport, using both self-assembled “sticky” pores and “sticky” nanoparticles to trigger transit across membranes. This combination links both fundamental and applied research, acting as a bridge between molecular level assembly and the formation of functional biomaterials. The ultimate goal is to create complex self-assembled systems in biological or biomimetic environments that can both interface with cells and transport compounds across bilayers in response to remote chemical or electromagnetic signals. Our research in this area started with fundamental studies of intramembrane and intermembrane self-assembly, building upon previously known channel-forming compounds to create self-assembled channels that were switchable or able to mediate vesicle–vesicle adhesion. Subsequently, nanoparticles with a “sticky” coating were used to mediate adhesion between vesicles. Combining these adhesive properties with the unique characteristics of nanosized magnetite allowed a noninvasive magnetic signal to trigger transport of compounds out of magnetic nanoparticle-vesicle assemblies. Adding an extravesicular matrix produced new responsive biomaterials for use in tissue engineering. These biomaterials can be magnetically patterned and can deliver drugs upon receipt of a magnetic signal, allowing spatiotemporal control over cellular responses.
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Affiliation(s)
- Simon J. Webb
- Manchester Institute of Biotechnology and the School of Chemistry, University of Manchester, 131 Princess St, Manchester M1 7DN, United Kingdom
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Abstract
Learning abstract rules is central to social and cognitive development. Across two experiments, we used Delayed Non-Matching to Sample tasks to characterize the longitudinal development and nature of rule-learning impairments in children with Autism Spectrum Disorder (ASD). Results showed that children with ASD consistently experienced more difficulty learning an abstract rule from a discrete physical reward than children with DD. Rule learning was facilitated by the provision of more concrete reinforcement, suggesting an underlying difficulty in forming conceptual connections. Learning abstract rules about social stimuli remained challenging through late childhood, indicating the importance of testing executive functions in both social and non-social contexts.
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Affiliation(s)
- E J H Jones
- Center on Child Health, Behavior and Development, Seattle Children’s Hospital, Seattle, Washington, USA
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Pike SJ, De Poli M, Zawodny W, Raftery J, Webb SJ, Clayden J. Diastereotopic fluorine substituents as 19F NMR probes of screw-sense preference in helical foldamers. Org Biomol Chem 2013; 11:3168-76. [DOI: 10.1039/c3ob40463c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Noble GT, Craven FL, Voglmeir J, Šardzík R, Flitsch SL, Webb SJ. Accelerated Enzymatic Galactosylation of N-Acetylglucosaminolipids in Lipid Microdomains. J Am Chem Soc 2012; 134:13010-7. [DOI: 10.1021/ja302506t] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Gavin T. Noble
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Faye L. Craven
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Josef Voglmeir
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Robert Šardzík
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Sabine L. Flitsch
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Simon J. Webb
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
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48
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de Cogan F, Booth A, Gough JE, Webb SJ. Conversion of magnetic impulses into cellular responses by self-assembled nanoparticle-vesicle hydrogels. Angew Chem Int Ed Engl 2011; 50:12290-3. [PMID: 22025452 DOI: 10.1002/anie.201103469] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 08/16/2011] [Indexed: 11/08/2022]
Affiliation(s)
- Felicity de Cogan
- School of Chemistry and Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess St, Manchester M1 7DN, UK
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de Cogan F, Gough JE, Webb SJ. Adhesive interactions between cells and biotinylated phospholipid vesicles in alginate: towards new responsive biomaterials. J Mater Sci Mater Med 2011; 22:1045-1051. [PMID: 21431355 DOI: 10.1007/s10856-011-4271-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 02/19/2011] [Indexed: 05/30/2023]
Abstract
Creating tissue-mimetic biomaterials able to deliver bioactive compounds after receipt of a remote and non-invasive trigger has so far proved to be challenging. The possible applications of such "smart" biomaterials are vast, ranging from subcutaneous drug delivery to tissue engineering. Self-assembled phospholipid vesicles (liposomes) have the ability to deliver both hydrophilic and hydrophobic drugs, and controlling interactions between functionalized vesicles and cells within biomaterials is an important step for targeted drug delivery to cells. We report an investigation of the interactions between thermally-sensitive and biotin-coated dipalmitoyl phosphatidylcholine vesicles and 3T3 fibroblast cells. The stability of these vesicles under physiological conditions was assessed and their interaction with the cell membranes of fibroblasts in media and alginate/fibronectin mixtures was studied. Stable vesicle-cell aggregates were formed in fluid matrices, and could be a model system for improving the delivery of remotely released drugs within vesicle-containing biomaterials.
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Affiliation(s)
- Felicity de Cogan
- School of Chemistry and Manchester Interdisciplinary Biocentre, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
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50
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Abstract
A membrane-spanning bis(meso-3-pyridyl) porphyrin 1 has been synthesized, embedded in EYPC vesicles, and upon Pd(II) addition has been shown to form ionophores that allow the passage of anionic 5/6-carboxyfluorescein through membranes. The geometric matching of bis(meso-3-pyridyl) porphyrin 1 and trans-Pd(II) was designed to give a cyclic porphyrin trimer [PdCl(2)(1)](3). However, solution-phase studies showed that PdCl(2)(PhCN)(2) cross linked 1 into linear oligomers at porphyrin concentrations above 10 mM, although the formation of cyclic species was inferred from studies at concentrations below 2 μM. Fluorescence titrations showed that embedding porphyrin 1 in bilayers greatly reduced its affinity for Pd(II), but the combination of porphyrin 1 and Pd(II) gave an ionophoric species that increased the rate of 5/6-carboxyfluorescein (5/6-CF) transit through the phospholipid bilayer 12-fold. A maximum in the 5/6-CF release rate was observed at a Pd(II) concentration of 4 μM, and the application of a solution-phase binding model to the membrane phase showed that this peak in ionophoric activity corresponded to the greatest extent of porphyrin oligomerization. Further studies suggested these Pd(II)/porphyrin oligomers transported 5/6-CF via a channel mechanism.
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Affiliation(s)
- Usha Devi
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, United Kingdom
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