- Metal ion induced allosteric transition in the catalytic activity of an artificial phosphodiesterase
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An artificial phosphodiesterase (1) bearing two types of metal binding sites, a catalytic site and a regulatory bipyridine site showed a unique allosteric transition in the catalytic activity against the metal concentration. The rate constants for the hydrolysis reaction of 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) and RNA dimer (ApA) with and without an effector metal ion were evaluated; the kobs value of HPNP hydrolysis for 1?(Zn 2+)3 (2.0 × 10-4 s-1) is 3.3 times larger than that for 1?(Zn2+)2. In the case of 1 and Cu2+, a 19.4 times larger kobs value was obtained for 1?(Cu2+)3 (1.2 × 10-3 s -1) against 1?(Cu2+)2. The increase in the catalytic activity is ascribed to the allosteric conformational transition of 1 induced by the coordination of effector metal ion to the Bpy moiety. A detailed investigation revealed that a conformational change of 1 induced by the third M2+ complexation enhances the rate of hydrolysis rather than a change in the substrate affinity. The Royal Society of Chemistry 2008.
- Takebayashi, Shinji,Shinkai, Seiji,Ikeda, Masato,Takeuchi, Masayuki
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Read Online
- Tropos, nevertheless conformationally stable biphenyl derivatives
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Biphenyl derivatives with small substituents in the ortho and ortho′ positions are called tropos. Due to the low rotation barrier around the C-C bond connecting the two phenyl units, the isolation of only one conformer is not possible; thus they are conformationally unstable. Using DFT calculations, we were able to show that using a suitable peptidic bridging unit, biphenyl systems can become conformationally stable. This stabilization should be independent of the type of substituent in the ortho and ortho′ positions. Some of the proposed biphenyl derivatives were successfully synthesized and studied in solution and solid state. The recorded VT-NMR, 2D-NMR and CD spectra show that all biphenyl derivatives exhibit the P conformation. The preference for the P conformation is confirmed by the structure of a biphenyl derivative in solid state.
- Haberhauer, Gebhard,Tepper, Christina,Woelper, Christoph,Blaeser, Dieter
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Read Online
- Design, synthesis and biological evaluation of low molecular weight CXCR4 ligands
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The chemokine receptor CXCR4/stromal cell-derived factor-1 (SDF-1: CXCL12) signaling axis represents a crucial drug target due to its relevance to several diseases such as HIV-1 infection, cancer, leukemia, and rheumatoid arthritis. With the aim of enhancing the binding affinity and anti-HIV activity of a potent CXCR4 ligand as a lead, 23 low molecular weight compounds containing dipicolylamine (Dpa) and cyclam cationic moieties with varying spacers and spatial positioning were designed, synthesized and biologically evaluated. All of the synthesized compounds screened at 1.0 μM in the NanoBRET assay system exhibited >70% inhibition of the binding of a competitive probe TAMRA-Ac-TZ14011 (10 nM) to CXCR4 in the presence of zinc (II) ion. Furthermore, selected compounds 3, 8, 9, 19 and 21 with spatial distances between the next carbon to Dpa and the next carbon to cyclam within the range of 6.5–7.5 ? showed potent binding affinity selective for CXCR4 with IC50 values of 1.6, 7.9, 5.7, 3.5 and 4.5 nM, respectively, with corresponding high anti-HIV activity with EC50s of 28, 13, 21, 28 and 61 nM, respectively, in the presence of zinc (II) ion. Some compounds with remarkably more potent CXCR4-binding affinity than that of an initial lead were obtained. These compounds interact with different but overlapping amino acid residues of CXCR4. The present studies have developed new low molecular weight CXCR4 ligands with high CXCR4-binding and anti-HIV activities, which open avenue into the development of more potent CXCR4 ligands.
- Sakyiamah, Maxwell M.,Kobayakawa, Takuya,Fujino, Masayuki,Konno, Makoto,Narumi, Tetsuo,Tanaka, Tomohiro,Nomura, Wataru,Yamamoto, Naoki,Murakami, Tsutomu,Tamamura, Hirokazu
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supporting information
p. 1130 - 1138
(2019/02/16)
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- IMMUNE CHECKPOINT INHIBITORS, COMPOSITIONS AND METHODS THEREOF
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The present invention provides synthesis, pharmaceutically acceptable formulations and uses of compounds in accordance with Formula (I), or a stereoisomer, a tautomer or a pharmaceutically acceptable salt thereof. For Formula (I) compounds R1, R2, X1, Y1 and n are as defined in the specification. The inventive Formula (I) compounds are inhibitors of the PD-1/PD-L1 protein/protein binding or functional interaction and find utility in any number of therapeutic applications, including but not limited to treatment of proliferative disorders such as cancer and infectious diseases.
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Paragraph 0225
(2018/03/25)
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- Enantioselective Anion Recognition by Chiral Halogen-Bonding [2]Rotaxanes
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The application of chiral interlocked host molecules for discrimination of guest enantiomers has been largely overlooked, which is surprising given their unique three-dimensional binding cavities capable of guest encapsulation. Herein, we combined the stringent linear geometric interaction constraints of halogen bonding (XB), the noncovalent interaction between an electrophilic halogen atom and a Lewis base, with highly preorganized and conformationally restricted chiral cavities of [2]rotaxanes to achieve enantioselective anion recognition. Representing the first detailed investigation of the use of chiral XB rotaxanes for this purpose, extensive 1H NMR binding studies and molecular dynamics (MD) simulation experiments revealed that the chiral rotaxane cavity significantly enhances enantiodiscrimination compared to the non-interlocked free axle and macrocycle components. Furthermore, by examining the enantioselectivities of a family of structurally similar XB [2]rotaxanes containing different combinations of chiral and achiral macrocycle and axle components, the dominant influence of the chiral macrocycle in our rotaxane design for determining the effectiveness of chiral discrimination is demonstrated. MD simulations reveal the crucial geometric roles played by the XB interactions in orientating the bound enantiomeric anion guests for chiral selectivity, as well as the critical importance of the anions' hydration shells in governing binding affinity and enantiodiscrimination.
- Lim, Jason Y. C.,Marques, Igor,Félix, Vítor,Beer, Paul D.
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supporting information
p. 12228 - 12239
(2017/09/12)
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- Design, synthesis and in vitro evaluation of novel bivalent S-adenosylmethionine analogues
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In optimal cases, bivalent ligands can bind with exceptionally high affinity to their protein targets. However, designing optimised linkers, that orient the two binding groups perfectly, is challenging, and yet crucial in both fragment-based ligand design
- Joce, Catherine,White, Rebecca,Stockley, Peter G.,Warriner, Stuart,Turnbull, W. Bruce,Nelson, Adam
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supporting information; experimental part
p. 278 - 284
(2012/03/11)
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- Dinuclear zinc(II) dithiocarbamate macrocycles: Ditopic receptors for a variety of guest molecules
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The synthesis of a series of dinuclear zinc(II) dithiocarbamate (dtc) macrocyclic receptors containing aryl spacer groups of different sizes is reported. As evidenced from 1H NMR titration investigations, these receptors have the ability to bin
- Wong, Wallace W. H.,Curiel, David,Cowley, Andrew R.,Beer, Paul D.
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p. 359 - 364
(2007/10/03)
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- Novel self-assembly of m-xylylene type dithioureas by head-to-tail hydrogen bonding
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Dithiourea la self-assembles to form an orthogonal dimer structure both in solution and in the solid state, wherein the four thiourea groups establish a closed network of hydrogen bonds through a head-to-tail binding mode. This novel dimer structure was elucidated on the basis of 1H NMR spectra, vapor pressure osmometry, and X-ray crystal structure analysis. Furthermore, a series of m-xylylene type dithioureas were synthesized and their dimerization constants (Ka) in CDCl3 were determined by dilution experiments using 1H NMR spectroscopy. The magnitude of the Ka values are dependent on the steric bulk of the side chains, the acidity of the thiourea groups, and the weak intermolecular interaction between the benzene rings of the side chains and the m-xylylene spacer.
- Tobe, Yoshito,Sasaki, Shin-Ichi,Mizuno, Masaaki,Hirose, Keiji,Naemura, Koichiro
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p. 7481 - 7489
(2007/10/03)
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- Axially chiral catenanes and π-electron-deficient receptors
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The design of a new class of chiral [2]catenanes is reported. The self-assembly of [2]catenanes comprising one or two 3,3'-biotyl spacers in the π-electron-deficient component, and bis-p-phenylene-34-crown-10 (BPP34C10) as the π-electron-rich component, i
- Asakawa, Masumi,Ashton, Peter R.,Boyd, Sue E.,Brown, Christopher L.,Menzer, Stephan,Pasini, Dario,Stoddart, J. Fraser,Tolley, Malcolm S.,White, Andrew J. P.,Williams, David J.,Wyatt, Paul G.
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p. 463 - 481
(2007/10/03)
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- Synthesis and Photocyclization of -, - and Cyclophanediene
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Three cyclophanes, -, - and cyclophanediene, 1, 5 and 6, respectively, have been prepared by double Wittig reactions.On irradiation under oxidative conditions, cyclophanes 1 and 6 give bi-4,5-phenanthrylene, 2, and (3,6)-p
- Thulin, Bengt,Wennerstroem, Olof
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p. 297 - 302
(2007/10/02)
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