101
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Hopkinson RJ, Barlow PS, Schofield CJ, Claridge TDW. Studies on the reaction of glutathione and formaldehyde using NMR. Org Biomol Chem 2010; 8:4915-20. [PMID: 20737071 DOI: 10.1039/c0ob00208a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Within cells it is proposed that a major mechanism for the metabolism of formaldehyde is via its reaction with glutathione (GSH) to form S-hydroxymethylglutathione (HMG), which undergoes subsequent oxidation. In addition to HMG and the previously reported (5R,10S)-5-(carboxymethylcarbamoyl)-7-oxo-3-thia-1,6-diazabicyclo[4.4.1]undecane-10-carboxylic acid (BiGF(2)), NMR studies on the reaction of GSH with formaldehyde reveal two previously unassigned monocyclic structures. The results imply that the biologically relevant reactions between aldehydes and peptides/proteins may be more complex than presently perceived.
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102
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Leung IKH, Flashman E, Yeoh KK, Schofield CJ, Claridge TDW. Using NMR solvent water relaxation to investigate metalloenzyme-ligand binding interactions. J Med Chem 2010; 53:867-75. [PMID: 20025281 DOI: 10.1021/jm901537q] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This report demonstrates that solvent water relaxation measurements can be used for quantitative screening of ligand binding and for mechanistic investigations of enzymes containing paramagnetic metal centers by using conventional NMR instrumentation at high field. The method was exemplified using prolyl hydroxylase domain containing enzyme 2 (PHD2), a human enzyme involved in hypoxic sensing, with Mn(II) substituting for Fe(II) at the active site. K(D) values were determined for inhibitors that hinder access of water to the paramagnetic center. This technique is also useful for investigating the mechanism of suitable metalloenzymes, including order of ligand binding and modes of inhibition.
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103
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Kemper S, Patel MK, Errey JC, Davis BG, Jones JA, Claridge TDW. Group epitope mapping considering relaxation of the ligand (GEM-CRL): including longitudinal relaxation rates in the analysis of saturation transfer difference (STD) experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 203:1-10. [PMID: 20022272 DOI: 10.1016/j.jmr.2009.11.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/20/2009] [Accepted: 11/23/2009] [Indexed: 05/28/2023]
Abstract
In the application of saturation transfer difference (STD) experiments to the study of protein-ligand interactions, the relaxation of the ligand is one of the major influences on the experimentally observed STD factors, making interpretation of these difficult when attempting to define a group epitope map (GEM). In this paper, we describe a simplification of the relaxation matrix that may be applied under specified experimental conditions, which results in a simplified equation reflecting the directly transferred magnetisation rate from the protein onto the ligand, defined as the summation over the whole protein of the protein-ligand cross-relaxation multiplied by with the fractional saturation of the protein protons. In this, the relaxation of the ligand is accounted for implicitly by inclusion of the experimentally determined longitudinal relaxation rates. The conditions under which this "group epitope mapping considering relaxation of the ligand" (GEM-CRL) can be applied were tested on a theoretical model system, which demonstrated only minor deviations from that predicted by the full relaxation matrix calculations (CORCEMA-ST) [7]. Furthermore, CORCEMA-ST calculations of two protein-saccharide complexes (Jacalin and TreR) with known crystal structures were performed and compared with experimental GEM-CRL data. It could be shown that the GEM-CRL methodology is superior to the classical group epitope mapping approach currently used for defining ligand-protein proximities. GEM-CRL is also useful for the interpretation of CORCEMA-ST results, because the transferred magnetisation rate provides an additional parameter for the comparison between measured and calculated values. The independence of this parameter from the above mentioned factors can thereby enhance the value of CORCEMA-ST calculations.
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104
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Hopkinson RJ, Hamed RB, Rose NR, Claridge TDW, Schofield CJ. Monitoring the Activity of 2-Oxoglutarate Dependent Histone Demethylases by NMR Spectroscopy: Direct Observation of Formaldehyde. Chembiochem 2010; 11:506-10. [DOI: 10.1002/cbic.200900713] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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105
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Hamed RB, Mecinović J, Ducho C, Claridge TDW, Schofield CJ. Carboxymethylproline synthase catalysed syntheses of functionalised N-heterocycles. Chem Commun (Camb) 2010; 46:1413-5. [PMID: 20162132 DOI: 10.1039/b924519g] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The utility of wild-type and variant carboxymethylproline synthases for biocatalysis was demonstrated by preparing functionalised 5-, 6- and 7-membered N-heterocycles from amino acid aldehydes and (alkylated) malonyl-coenzyme A derivatives; the N-heterocycles produced were converted to the corresponding bicyclic beta-lactams by a carbapenem synthetase.
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106
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Robertson J, Feast GC, White LV, Steadman (née Doughty) VA, Claridge TDW. Structure and reactivity of bicyclic methylene aziridines prepared by intramolecular aziridination of allenes. Org Biomol Chem 2010; 8:3060-3. [DOI: 10.1039/c003693e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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107
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Hamed RB, Batchelar ET, Mecinović J, Claridge TDW, Schofield CJ. Evidence that Thienamycin Biosynthesis Proceeds via C-5 Epimerization: ThnE Catalyzes the Formation of (2S,5S)-trans-Carboxymethylproline. Chembiochem 2009; 10:246-50. [DOI: 10.1002/cbic.200800652] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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108
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Hamed RB, Batchelar ET, Mecinović J, Claridge TDW, Schofield CJ. Cover Picture: Evidence that Thienamycin Biosynthesis Proceeds via C-5 Epimerization: ThnE Catalyzes the Formation of (2 S,5 S)- trans-Carboxymethylproline (ChemBioChem 2/2009). Chembiochem 2009. [DOI: 10.1002/cbic.200990000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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109
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Pérez-Victoria I, Kemper S, Patel MK, Edwards JM, Errey JC, Primavesi LF, Paul MJ, Claridge TDW, Davis BG. Saturation transfer difference NMR reveals functionally essential kinetic differences for a sugar-binding repressor protein. Chem Commun (Camb) 2009:5862-4. [DOI: 10.1039/b913489a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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110
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Iqbal A, Clifton IJ, Bagonis M, Kershaw NJ, Domene C, Claridge TDW, Wharton CW, Schofield CJ. Anatomy of a Simple Acyl Intermediate in Enzyme Catalysis: Combined Biophysical and Modeling Studies on Ornithine Acetyl Transferase. J Am Chem Soc 2008; 131:749-57. [DOI: 10.1021/ja807215u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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111
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Batchelar ET, Hamed RB, Ducho C, Claridge TDW, Edelmann MJ, Kessler B, Schofield CJ. Thioester hydrolysis and C-C bond formation by carboxymethylproline synthase from the crotonase superfamily. Angew Chem Int Ed Engl 2008; 47:9322-5. [PMID: 18972478 DOI: 10.1002/anie.200803906] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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112
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Claridge TDW, Davies SG, Polywka MEC, Roberts PM, Russell AJ, Savory ED, Smith AD. “Pure by NMR”? Org Lett 2008; 10:5433-6. [DOI: 10.1021/ol802211p] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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113
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Purser S, Claridge TDW, Odell B, Moore PR, Gouverneur V. A Two-Directional Approach to Enantiopure 1,4-Difluoro-cyclohexenes: Synthesis of Difluorinated Cyclitol Analogues. Org Lett 2008; 10:4263-6. [DOI: 10.1021/ol8017402] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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114
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Aciro C, Claridge TDW, Davies SG, Roberts PM, Russell AJ, Thomson JE. Ammonium-directed dihydroxylation of 3-aminocyclohex-1-enes: development of a metal-free dihydroxylation protocol. Org Biomol Chem 2008; 6:3751-61. [PMID: 18843405 DOI: 10.1039/b808811j] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Treatment of 3-aminocyclohex-1-enes with mCPBA in the presence of trichloroacetic acid gives the corresponding 1,2-anti-2,3-syn-1-trichloroacetoxy-2-hydroxy-3-aminocyclohexane with high levels of diastereoselectivity (90% de). This is consistent with a mechanism of oxidation involving hydrogen-bonded delivery of the oxidant by the allylic ammonium ion formed in situ, followed by highly regioselective ring-opening of the intermediate epoxide by trichloroacetic acid. The effect of conformational constraints upon the oxidation reaction is also examined.
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115
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Miller GA, Islam MS, Claridge TDW, Dodgson T, Simpson SJ. Swarm formation in the desert locust Schistocerca gregaria:isolation and NMR analysis of the primary maternal gregarizing agent. J Exp Biol 2008; 211:370-6. [DOI: 10.1242/jeb.013458] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Depending on their rearing density, female desert locusts Schistocerca gregaria epigenetically endow their offspring with differing phenotypes. To identify the chemical basis for such maternal transmission, we compared solitarious and gregarious locust egg pod foam using high performance liquid chromatography (HPLC). We revealed causal relationships between foam chemistry and hatchling phenotype (phase state) by iteratively applying HPLC fractions from gregarious locust egg foam extracts to solitarious eggs and assessing resulting hatchlings with a behavioural bioassay involving logistic regression. Selection and application of increasingly specific HPLC fractions allowed us to isolate compounds with gregarizing properties. Hatchling gregarization was triggered only by certain fractions and was dose dependent. In a final series of experiments, we characterized the most specific gregarizing fraction by nuclear magnetic resonance (NMR) spectroscopy. Here we present tentative structural features of the primary locust maternal gregarizing agent, which appears to be an alkylated l-dopa analogue. In addition, we propose a mechanism for phase-dependent regulation of this compound's activity.
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116
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Carroll L, McCullough S, Rees T, Claridge TDW, Gouverneur V. Stereospecific anti SE2′ fluorination of allenylsilanes: synthesis of enantioenriched propargylic fluorides. Org Biomol Chem 2008; 6:1731-3. [DOI: 10.1039/b803888k] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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117
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Kaewpet M, Odell B, King MA, Banerji B, Schofield CJ, Claridge TDW. Synthesis and conformational analysis of cyclic analogues of inverse γ-turns. Org Biomol Chem 2008; 6:3476-85. [DOI: 10.1039/b808954j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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118
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Frampton MJ, Claridge TDW, Latini G, Brovelli S, Cacialli F, Anderson HL. Amylose-wrapped luminescent conjugated polymers. Chem Commun (Camb) 2008:2797-9. [DOI: 10.1039/b803335h] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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119
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Madikane VE, Bhakta S, Russell AJ, Campbell WE, Claridge TDW, Elisha BG, Davies SG, Smith P, Sim E. Inhibition of mycobacterial arylamine N-acetyltransferase contributes to anti-mycobacterial activity of Warburgia salutaris. Bioorg Med Chem 2007; 15:3579-86. [PMID: 17368035 DOI: 10.1016/j.bmc.2007.02.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 02/02/2007] [Accepted: 02/08/2007] [Indexed: 01/11/2023]
Abstract
In this study, we show that extracts and a purified compound of Warburgia salutaris exhibit anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv and Mycobacterium bovis BCG Pasteur. The extracts did not inhibit growth of Escherichia coli and were not toxic to cultured mammalian macrophage cells at the concentrations at which anti-mycobacterial activity was observed. The extract and pure compound inhibited pure recombinant arylamine N-acetyltransferase (NAT), an enzyme involved in mycobacterial cell wall lipid synthesis. Moreover, neither extract nor pure compound inhibited growth of a strain of M. bovis BCG in which nat has been deleted suggesting that NAT may indeed be a target within the mycobacterial cell. The purified compound is a novel drimane sesquiterpenoid lactone, 11alpha-hydroxycinnamosmolide. These studies show that W. salutaris is a useful source of anti-tubercular compounds for further analysis and supports the hypothesis of a link between NAT inhibition and anti-mycobacterial activity.
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120
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Cheetham AG, Claridge TDW, Anderson HL. Metal-driven ligand assembly in the synthesis of cyclodextrin [2] and [3]rotaxanes. Org Biomol Chem 2007; 5:457-62. [PMID: 17252128 DOI: 10.1039/b616621k] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclodextrin [2] and [3]rotaxanes have been synthesised by use of a metal-driven ligand formation methodology. The kinetically stable cobalt(III) complexes formed act as either linking or capping groups, the function being selected by manipulation of the reaction conditions to promote the formation of either 2:1 or 1:1 complexes, respectively. In all cases, mixtures of isomers containing different alpha-cyclodextrin orientations were observed. All three orientational isomers of the [3]rotaxane were isolated and structurally characterized by 2D NMR.
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121
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Purser S, Odell B, Claridge TDW, Moore PR, Gouverneur V. Sequential Desymmetrization–Fluorination: Enantioselective Synthesis of Fluorinated Cyclitols. Chemistry 2006; 12:9176-85. [PMID: 17066392 DOI: 10.1002/chem.200600861] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An asymmetric synthesis of enantioenriched, highly functionalized fluorinated carbocycles has been developed based on an enantioselective Sharpless dihydroxylation of cyclohexadienylsilanes, combined with a diastereoselective electrophilic fluorodesilylation. Several parameters define the level of diastereocontrol for the fluorination step. These include the relative stereochemistry of the starting endocyclic allylsilanes and the structural features of the reactants. As expected for an S(E)2' mechanism, the fluorodesilylation occurred with clean transposition of the double bond, with the attack of the electrophilic fluorinating agent taking place preferentially anti to the silyl group. For the fluorination step, the best selectivities were observed for the monocyclic anti,syn benzyl-protected precursors and for the syn,syn starting allylsilane. Full NMR spectroscopic analysis of the fluorinated monocyclic compounds, which possess an endocyclic double bond flanked by two electronegative groups (the methoxy group and the fluorine substituent) revealed that a subtle combination of steric (1,3-axial/pseudoaxial interaction) and stereoelectronic effects (pi-sigma* interaction) favours the preferential conformers featuring the methoxy group in a pseudoaxial position.
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122
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Rising TWDF, Claridge TDW, Moir JWB, Fairbanks AJ. Endohexosaminidase M: exploring and exploiting enzyme substrate specificity. Chembiochem 2006; 7:1177-80. [PMID: 16800015 DOI: 10.1002/cbic.200600183] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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123
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Rising TWDF, Claridge TDW, Davies N, Gamblin DP, Moir JWB, Fairbanks AJ. Synthesis of N-glycan oxazolines: donors for endohexosaminidase catalysed glycosylation. Carbohydr Res 2006; 341:1574-96. [PMID: 16584712 DOI: 10.1016/j.carres.2006.03.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 02/24/2006] [Accepted: 03/07/2006] [Indexed: 11/20/2022]
Abstract
Oxazoline mono-, di-, tri- and hexasaccharides, corresponding to the core components of N-linked glycoprotein high mannose glycans, are synthesised as potential glycosyl donors for endohexosaminidase catalysed glycosylation of glycopeptides and glycoprotein remodelling. The crucial beta-D-Manp-(1-->4)-D-GlcpNAc linkage is synthesised via epimerisation of gluco disaccharide substrates by sequential triflation and nucleophilic substitution. Oxazolines are formed directly from the anomeric OPMP protected N-acetyl glucosamine derivatives. Efficient endohexosaminidase catalysed glycosylation of a synthetic beta-D-GlcpNAcAsn glycosyl amino acid is demonstrated with the trisaccharide oxazoline donor.
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124
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McNeill LA, Flashman E, Buck MRG, Hewitson KS, Clifton IJ, Jeschke G, Claridge TDW, Ehrismann D, Oldham NJ, Schofield CJ. Hypoxia-inducible factor prolyl hydroxylase 2 has a high affinity for ferrous iron and 2-oxoglutarate. MOLECULAR BIOSYSTEMS 2005; 1:321-4. [PMID: 16880998 DOI: 10.1039/b511249b] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Regulation of the hypoxic response in humans is regulated by the post-translational hydroxylation of hypoxia inducible transcription factor; a recombinant form of a human prolyl-4-hydroxylase (PHD2) was characterised and shown to have an unexpectedly high affinity for, and to copurify with endogenous levels of, its Fe(ii) cofactor and 2-oxoglutarate cosubstrate.
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125
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Claridge TDW, Long DD, Baker CM, Odell B, Grant GH, Edwards AA, Tranter GE, Fleet GWJ, Smith MD. Helix-Forming Carbohydrate Amino Acids. J Org Chem 2005; 70:2082-90. [PMID: 15760191 DOI: 10.1021/jo0480040] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] The solution-phase conformational properties of tetrameric and octameric chains of C-glycosyl alpha-d-lyxofuranose configured tetrahydrofuran amino acids (where the C-2 and C-5 substituents on the tetrahydrofuran ring are trans to each other) were examined using NMR and IR and CD in organic solvents. Studies by NMR and IR demonstrated that in chloroform solution, the tetramer 7 does not adopt a hydrogen-bonded conformation whereas the octamer 10 populates a well-defined helical secondary structure stabilized by 16-membered (i, i - 3) interresidue hydrogen bonds, similar to a pi-helix. Circular dichroism studies in trifluoroethanol are consistent with this conformation for the octamer 10, and also indicate that the tetramer 7 adopts a rigid conformation not stabilized by hydrogen bonds.
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126
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Carmichael D, Ricard L, Seeboth N, Brown JM, Claridge TDW, Odell B. Synthesis, structure and dynamics of methoxynaphthalene-substituted phospha-ruthenocenes and -ferrocenes. Dalton Trans 2005:2173-81. [PMID: 15957060 DOI: 10.1039/b418926d] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The syntheses of potassium 2-(2'-methoxynaphth-1'-yl)-3,4-dimethyl-5-phenylphospholide 4 and eta5-pentamethylcyclopentadienyl(eta5-2-(2-methoxynaphth-1-yl)-3,4-dimethyl-5-phenylphospholyl)-ruthenium(II)5 and -iron(II)6 are described. The barrier to rotation of the naphthyl group (79 kJ mol-1 and 72 kJ mol-1 in CD2Cl2 respectively) characterises 5 and 6 as potential tropos type ligands. Coordination of 5 to [PtCl2(PEt3)] gives two cis and two trans complexes [PtCl2(PEt3)5] wherein rotation about the phospholyl-naphthyl vector is slow.
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127
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Johnson SW, Jenkinson SF, Pérez-Victoria I, Edwards AA, Claridge TDW, Tranter GE, Fleet GWJ, Jones JH. Conformational studies of oligomeric oxetane-based dipeptide isosteres derived fromL-rhamnose orD-xylose. J Pept Sci 2005; 11:517-24. [PMID: 15884104 DOI: 10.1002/psc.658] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Conformational investigations have been undertaken on oligomers (dimers, tetramers, hexamers) of five closely related oxetane-based dipeptide isosteres. All the oligomers were subjected to a range of studies by NMR, FT-IR and CD spectroscopy. The oligomers derived from methyl 2,4-anhydro-5-azido-3-O-tert-butyldimethylsilyl-5-deoxy-L-rhamnonate 'monomer' all exhibited evidence of ordered conformations in chloroform and 2,2,2-trifluoroethanol (TFE) solution. 5-Acetamido and N-methylamide derivatives of the L-rhamnonate 'monomer', along with a 'dimer' lacking silyl protection at C-3, were synthesized to ascertain the role of intramolecular interactions. This led to the conclusion that, for the L-rhamnonate oligomers, steric interactions govern the conformational preference observed. The equivalent silyl-protected D-lyxonate oligomers gave ordered CD spectra in TFE solution, but NMR and FT-IR spectroscopy in chloroform solution suggested an irregular, non-hydrogen bonded system. The remaining silyl-protected 6-deoxy-L-altronate, 6-deoxy-D-gulonate and D-fuconate oligomers appear to be characterized by their lack of ordered conformation in TFE and chloroform solution.
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128
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Johnson SW, Jenkinson SF, Angus D, Pérez-Victoria I, Claridge TDW, Fleet GWJ, Jones JH. The synthesis of oligomers of oxetane-based dipeptide isosteres derived fromL-rhamnose orD-xylose. J Pept Sci 2005; 11:303-18. [PMID: 15968624 DOI: 10.1002/psc.622] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Routes to oligomers (dimers, tetramers, hexamers) of five oxetane-based dipeptide isosteres have been established. Methyl 2,4-anhydro-5-azido-5-deoxy-L-rhamnonate 'monomer' led, by coupling the corresponding carboxylic acid and amine, to a 'dimer'. Reverse-aldol ring-opening occurred on attempted saponification of the dimer, so all further oligomerization was performed using TBDMS C-3 hydroxyl protection. The silyl protected L-rhamnonate monomer led in turn to the dimer (via the monomer acid and amine), the tetramer (via the dimer acid and amine) and finally the hexamer (via the tetramer acid and dimer amine). In each case the acids were obtained through saponification of the respective methyl esters and the amines were obtained by hydrogenation of the azides; coupling was TBTU-mediated. Essentially the same strategy was employed on equivalent D-lyxonate, 6-deoxy-L-altronate, 6-deoxy-D-gulonate and D-fuconate dipeptide isosteres to give the respective dimers, tetramers and hexamers.
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129
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Chung YK, Claridge TDW, Fleet GWJ, Johnson SW, Jones JH, Lumbard KW, Stachulski AV. Scientific Content P1–P85. J Pept Sci 2004. [PMID: 14959886 PMCID: PMC7167831 DOI: 10.1002/psc.615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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130
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Chung YK, Claridge TDW, Fleet GWJ, Johnson SW, Jones JH, Lumbard KW, Stachulski AV. An unsaturated peptidomimetic assembly derived from a carbohydrate. J Pept Sci 2004; 10:1-7. [PMID: 14959886 PMCID: PMC7167831 DOI: 10.1002/psc.488] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A strategy has been established for the synthesis of peptidomimetics derived from unsaturated carbohydrates, and exemplified by the use of methyl 2,6-anhydro-7-azido-3,7-deoxy-4,5-O-isopropylidene-D-lyxo-hept-2-enonate 9 as a dipeptide 'monomer' which can be elaborated from either end. Selective reduction of 9 gives a protected pseudodipeptide ester suitable for use as an amino component, and saponification gives an azido acid suitable for use as a carboxyl component. The 'dimer' product of coupling these two components with TBTU can be similarly elaborated at either end to give a 'trimer' and a further cycle of selective reduction and coupling gave a 'tetramer', 17, a pseudo-octapeptide.
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131
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Maughan MAT, Davies IG, Claridge TDW, Courtney S, Hay P, Davis BG. Nitrogen inversion as a diastereomeric relay in azasugar synthesis: the first synthesis of adenophorine. Angew Chem Int Ed Engl 2003; 42:3788-92. [PMID: 12923845 DOI: 10.1002/anie.200351002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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132
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Maughan MAT, Davies IG, Claridge TDW, Courtney S, Hay P, Davis BG. Nitrogen Inversion as a Diastereomeric Relay in Azasugar Synthesis: The First Synthesis of Adenophorine. Angew Chem Int Ed Engl 2003. [DOI: 10.1002/ange.200351002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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133
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Moses JE, Baldwin JE, Marquez R, Adlington RM, Claridge TDW, Odell B. Biomimetic synthesis of the crispatene core. Org Lett 2003; 5:661-3. [PMID: 12605484 DOI: 10.1021/ol020242z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The biomimetic synthesis of the crispatene core is reported. The core framework was efficiently generated from an easily synthesized all (E)-tetraene precursor in one step, in good yield.
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134
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Smith MD, Claridge TDW, Sansom MSP, Fleet GWJ. Bend ribbon-forming tetrahydrofuran amino acidsThis is one of a number of contributions from the current members of the Dyson Perrins Laboratory to mark the end of almost 90 years of organic chemistry research in that building, as all its current academic staff move across South Parks Road to a new purpose-built laboratory. Org Biomol Chem 2003; 1:3647-55. [PMID: 14649895 DOI: 10.1039/b307707c] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Short oligomeric chains of C-glycosyl beta-D-arabinofuranose configured tetrahydrofuran amino acids (where the C-2 and C-5 substituents of the tetrahydrofuran ring are cis to each other) exhibit a well-defined repeating turn secondary structure stabilised by (i, i - 2) inter-residue hydrogen bonds. This is in contrast to the epimeric alpha-D-arabinofuranose oligomer (where the C-2 and C-5 substituents of the tetrahydrofuran ring are trans to each other) in which there is no indication of any secondary structure in solution.
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135
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Hon WC, Wilson MI, Harlos K, Claridge TDW, Schofield CJ, Pugh CW, Maxwell PH, Ratcliffe PJ, Stuart DI, Jones EY. Structural basis for the recognition of hydroxyproline in HIF-1 alpha by pVHL. Nature 2002; 417:975-8. [PMID: 12050673 DOI: 10.1038/nature00767] [Citation(s) in RCA: 547] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hypoxia-inducible factor-1 (HIF-1) is a transcriptional complex that controls cellular and systemic homeostatic responses to oxygen availability. HIF-1 alpha is the oxygen-regulated subunit of HIF-1, an alpha beta heterodimeric complex. HIF-1 alpha is stable in hypoxia, but in the presence of oxygen it is targeted for proteasomal degradation by the ubiquitination complex pVHL, the protein of the von Hippel Lindau (VHL) tumour suppressor gene and a component of an E3 ubiquitin ligase complex. Capture of HIF-1 alpha by pVHL is regulated by hydroxylation of specific prolyl residues in two functionally independent regions of HIF-1 alpha. The crystal structure of a hydroxylated HIF-1 alpha peptide bound to VCB (pVHL, elongins C and B) and solution binding assays reveal a single, conserved hydroxyproline-binding pocket in pVHL. Optimized hydrogen bonding to the buried hydroxyprolyl group confers precise discrimination between hydroxylated and unmodified prolyl residues. This mechanism provides a new focus for development of therapeutic agents to modulate cellular responses to hypoxia.
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136
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Hungerford NL, Claridge TDW, Watterson MP, Aplin RT, Moreno A, Fleet GWJ. Tetrahydrofuran amino acids: Secondary structure in tetrameric and octameric carbopeptoids derived from a D-allo 5-(aminomethyl)tetrahydrofuran-2-carboxylic acid. ACTA ACUST UNITED AC 2000. [DOI: 10.1039/b002996n] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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137
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Brittain DEA, Watterson MP, Claridge TDW, Smith MD, Fleet GWJ. Tetrahydrofuran amino acids—versatile building blocks for unnatural biopolymers: lack of secondary structure in oligomeric carbopeptoids derived from a D-galacto-5-(aminomethyl) tetrahydrofuran-2-carboxylic acid. ACTA ACUST UNITED AC 2000. [DOI: 10.1039/b002995p] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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138
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Baldwin JE, Claridge TDW, Culshaw AJ, Heupel FA, Lee V, Spring DR, Whitehead RC. Studies on the Biomimetic Synthesis of the Manzamine Alkaloids. Chemistry 1999. [DOI: 10.1002/(sici)1521-3765(19991105)5:11<3154::aid-chem3154>3.0.co;2-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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139
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Baldwin JE, Claridge TDW, Culshaw AJ, Heupel FA, Lee V, Spring DR, Whitehead RC, Boughtflower RJ, Mutton IM, Upton RJ. Investigations into the Manzamine Alkaloid Biosynthetic Hypothesis. Angew Chem Int Ed Engl 1998; 37:2661-2663. [DOI: 10.1002/(sici)1521-3773(19981016)37:19<2661::aid-anie2661>3.0.co;2-d] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/1998] [Indexed: 11/07/2022]
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140
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Baldwin JE, Claridge TDW, Culshaw AJ, Heupel FA, Lee V, Spring DR, Whitehead RC, Boughtflower RJ, Mutton IM, Upton RJ. Untersuchungen zur Hypothese der Manzaminalkaloid-Biosynthese. Angew Chem Int Ed Engl 1998. [DOI: 10.1002/(sici)1521-3757(19981002)110:19<2806::aid-ange2806>3.0.co;2-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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141
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Smith MD, Long DD, Claridge TDW, Fleet GWJ, Marquess DG, Marquess DG. Synthesis of oligomers of tetrahydrofuran amino acids: furanose carbopeptoids. Chem Commun (Camb) 1998. [DOI: 10.1039/a805364b] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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142
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Smith MD, Claridge TDW, Fleet GWJ, Tranter GE, Sansom MSP. Secondary structure in oligomers of carbohydrate amino acids. Chem Commun (Camb) 1998. [DOI: 10.1039/a805401k] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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143
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Hii KK, Claridge TDW, Brown JM. Intermediates in the Intermolecular, Asymmetric Heck Arylation of Dihydrofurans. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/anie.199709841] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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144
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Hii KK, Claridge TDW, Brown JM. Zwischenstufen in der intramolekularen asymmetrischen Heck-Arylierung von Dihydrofuranen. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971090925] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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145
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Westwood NJ, Schofield CJ, Claridge TDW. Studies on the reactivity of azetidin-2-ones in phosphate buffer. ACTA ACUST UNITED AC 1997. [DOI: 10.1039/a702673k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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146
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Ramsden JA, Claridge TDW, Brown JM. Structure and dynamics of intermediates in asymmetric hydrogenation by rhodium complexes of (2-methoxyphenyl)-P-phenyl-P-(2′-diphenylphosphino)ethylphosphine. ACTA ACUST UNITED AC 1995. [DOI: 10.1039/c39950002469] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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147
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Baldwin JE, Claridge TDW, Derome AE, Smith BD, Twyman M, Waley SG. Direct observation of a tetrahedral boronic acid–β-lactamase complex using11B NMR spectroscopy. ACTA ACUST UNITED AC 1991. [DOI: 10.1039/c39910000573] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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