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5. Au–Pd separation enhances bimetallic catalysis of alcohol oxidation

Author

Huang, Xiaoyang, Akdim, Ouardia, Douthwaite, Mark, Wang, Kai, Zhao, Liang, Lewis, Richard J., Pattisson, Samuel, Daniel, Isaac T., Miedziak, Peter J., Shaw, Greg, Morgan, David J., Althahban, Sultan M., Davies, Thomas E., He, Qian, Wang, Fei, Fu, Jile, Bethell, Donald, McIntosh, Steven, Kiely, Christopher J., and Hutchings, Graham J.

Published
2022
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9. Novel Scorpion Toxin ω-Buthitoxin-Hf1a Selectively Inhibits Calcium Influx via CaV3.3 and CaV3.2 and Alleviates Allodynia in a Mouse Model of Acute Postsurgical Pain

Author

Wang, Dan, primary, Herzig, Volker, additional, Dekan, Zoltan, additional, Rosengren, K. Johan, additional, Payne, Colton D., additional, Hasan, Md. Mahadhi, additional, Zhuang, Jiajie, additional, Bourinet, Emmanuel, additional, Ragnarsson, Lotten, additional, Alewood, Paul F., additional, and Lewis, Richard J., additional

Published
2024
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13. The application of Cs-exchanged tungstophosphoric acid as an additive in the direct synthesis of hydrogen peroxide and the use of Au-Pd/TS-1 in a one-pot approach to cyclohexanone oxime production

Author

Lewis, Richard J.

Subjects
547, QD Chemistry
Abstract

The work presented within this thesis can be separated into two distinct parts. The first investigates the direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen using gold-palladium supported catalysts and caesium exchanged tungstophosphoric acid as an acidic additive. The direct synthesis of H2O2 presents an environmentally friendly alternative to the current industrial, anthraquinone process. However for the direct route to be viable a variety of issues must be addressed. Primarily catalytic selectivity towards H2O2 is a major concern for the majority of catalysts active for H2O2 synthesis, with the degradation of H2O2 through hydrogenation or decomposition reported for a number of catalysts within the literature. The use of acid either during catalyst preparation or as part of the reaction solution has previously been shown to improve selectivity towards H2O2. Furthermore acidic supports, including heteropolyacid, have been observed to produce catalysts with greater selectivity than those with a higher isoelectric point and in turn provide higher yields of H2O2. This work investigates the ability of caesium exchanged heteropolyacids to improve catalytic activity towards H2O2 when used in addition to Au-Pd supported catalysts, in particular 2.5 wt. % Au - 2.5 wt. Pd/TiO2. The second part of this work is concerned with the ammoximation of cyclohexanone to cyclohexanone oxime via the in-situ formation of H2O2, in a one-pot style process. The conditions associated with ammoximation of cyclohexanone that is the presence of elevated temperatures and basic conditions, are considered extremely harsh for H2O2 stability. The in-situ generation of H2O2 during the ammoximation of cyclohexanone to cyclohexanone oxime would yield significant reductions in overall costs of the ammoximation reaction. Primarily these costs are associated with the purchasing, transport, storage and dilution of H2O2. This work determines the feasibility of a one-pot ammoximation process via in-situ H2O2 formation. Firstly, reaction conditions are established for this process and following this the role of catalyst design in improving selectivity towards cyclohexanone oxime as well as cyclohexanone conversion for this reaction is studied.

Published
2016

14. Some of the most interesting CASP11 targets through the eyes of their authors

Author

Kryshtafovych, Andriy, Moult, John, Baslé, Arnaud, Burgin, Alex, Craig, Timothy K, Edwards, Robert A, Fass, Deborah, Hartmann, Marcus D, Korycinski, Mateusz, Lewis, Richard J, Lorimer, Donald, Lupas, Andrei N, Newman, Janet, Peat, Thomas S, Piepenbrink, Kurt H, Prahlad, Janani, van Raaij, Mark J, Rohwer, Forest, Segall, Anca M, Seguritan, Victor, Sundberg, Eric J, Singh, Abhimanyu K, Wilson, Mark A, and Schwede, Torsten

Subjects
Biochemistry and Cell Biology, Bioinformatics and Computational Biology, Biological Sciences, Prevention, Bacteria, Computational Biology, Computer Graphics, Crystallography, X-Ray, Databases, Protein, Humans, International Cooperation, Models, Molecular, Models, Statistical, Protein Folding, Protein Interaction Domains and Motifs, Protein Multimerization, Protein Structure, Secondary, Proteins, Sequence Homology, Amino Acid, Software, Viruses, X-ray crystallography, NMR, CASP, protein structure prediction, Mathematical Sciences, Information and Computing Sciences, Bioinformatics, Biological sciences, Mathematical sciences
Abstract

The Critical Assessment of protein Structure Prediction (CASP) experiment would not have been possible without the prediction targets provided by the experimental structural biology community. In this article, selected crystallographers providing targets for the CASP11 experiment discuss the functional and biological significance of the target proteins, highlight their most interesting structural features, and assess whether these features were correctly reproduced in the predictions submitted to CASP11. Proteins 2016; 84(Suppl 1):34-50. © 2015 The Authors. Proteins: Structure, Function, and Bioinformatics Published by Wiley Periodicals, Inc.

Published
2016

17. Monitoring of tritium purity during long-term circulation in the KATRIN test experiment LOOPINO using laser Raman spectroscopy

Author

Fischer, Sebastian, Sturm, Michael, Schlösser, Magnus, Bornschein, Beate, Drexlin, Guido, Priester, Florian, Lewis, Richard J., and Telle, Helmut H.

Subjects
Physics - Instrumentation and Detectors, Physics - Optics
Abstract

The gas circulation loop LOOPINO has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK) to perform Raman measurements of circulating tritium mixtures under conditions similar to the inner loop system of the neutrino-mass experiment KATRIN, which is currently under construction. A custom-made interface is used to connect the tritium containing measurement cell, located inside a glove box, with the Raman setup standing on the outside. A tritium sample (purity > 95%, 20 kPa total pressure) was circulated in LOOPINO for more than three weeks with a total throughput of 770 g of tritium. Compositional changes in the sample and the formation of tritiated and deuterated methanes CT_(4-n)X_n (X=H,D; n=0,1) were observed. Both effects are caused by hydrogen isotope exchange reactions and gas-wall interactions, due to tritium {\beta} decay. A precision of 0.1% was achieved for the monitoring of the T_2 Q_1-branch, which fulfills the requirements for the KATRIN experiment and demonstrates the feasibility of high-precision Raman measurements with tritium inside a glove box.

Published
2012

18. Novel Scorpion Toxin ω-Buthitoxin-Hf1a Selectively Inhibits Calcium Influx via Ca V 3.3 and Ca V 3.2 and Alleviates Allodynia in a Mouse Model of Acute Postsurgical Pain.

Author

Wang, Dan, Herzig, Volker, Dekan, Zoltan, Rosengren, K. Johan, Payne, Colton D., Hasan, Md. Mahadhi, Zhuang, Jiajie, Bourinet, Emmanuel, Ragnarsson, Lotten, Alewood, Paul F., and Lewis, Richard J.

Subjects
SCORPION venom, POSTOPERATIVE pain, AMINO acid residues, LABORATORY mice, PEPTIDOMIMETICS, MEMBRANE proteins
Abstract

Venom peptides have evolved to target a wide range of membrane proteins through diverse mechanisms of action and structures, providing promising therapeutic leads for diseases, including pain, epilepsy, and cancer, as well as unique probes of ion channel structure-function. In this work, a high-throughput FLIPR window current screening assay on T-type CaV3.2 guided the isolation of a novel peptide named ω-Buthitoxin-Hf1a from scorpion Hottentotta franzwerneri crude venom. At only 10 amino acid residues with one disulfide bond, it is not only the smallest venom peptide known to target T-type CaVs but also the smallest structured scorpion venom peptide yet discovered. Synthetic Hf1a peptides were prepared with C-terminal amidation (Hf1a-NH2) or a free C-terminus (Hf1a-OH). Electrophysiological characterization revealed Hf1a-NH2 to be a concentration-dependent partial inhibitor of CaV3.2 (IC50 = 1.18 μM) and CaV3.3 (IC50 = 0.49 μM) depolarized currents but was ineffective at CaV3.1. Hf1a-OH did not show activity against any of the three T-type subtypes. Additionally, neither form showed activity against N-type CaV2.2 or L-type calcium channels. The three-dimensional structure of Hf1a-NH2 was determined using NMR spectroscopy and used in docking studies to predict its binding site at CaV3.2 and CaV3.3. As both CaV3.2 and CaV3.3 have been implicated in peripheral pain signaling, the analgesic potential of Hf1a-NH2 was explored in vivo in a mouse model of incision-induced acute post-surgical pain. Consistent with this role, Hf1a-NH2 produced antiallodynia in both mechanical and thermal pain. [ABSTRACT FROM AUTHOR]

Published
2024
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40. The structural conformation of the tachykinin domain drives the anti‐tumoural activity of an octopus peptide in melanoma BRAF V600E

Author

Moral‐Sanz, Javier, primary, Fernandez‐Rojo, Manuel A., additional, Colmenarejo, Gonzalo, additional, Kurdyukov, Sergey, additional, Brust, Andreas, additional, Ragnarsson, Lotten, additional, Andersson, Åsa, additional, Vila, Sabela F., additional, Cabezas‐Sainz, Pablo, additional, Wilhelm, Patrick, additional, Vela‐Sebastián, Ana, additional, Fernández‐Carrasco, Isabel, additional, Chin, Yanni K. Y., additional, López‐Mancheño, Yaiza, additional, Smallwood, Taylor B., additional, Clark, Richard J., additional, Fry, Bryan G., additional, King, Glenn F., additional, Ramm, Grant A., additional, Alewood, Paul F., additional, Lewis, Richard J., additional, Mulvenna, Jason P., additional, Boyle, Glen M., additional, Sanchez, Laura E., additional, Neely, G. Gregory, additional, Miles, John J., additional, and Ikonomopoulou, Maria P., additional

Published
2022
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43. Importance of Binding Site Hydration and Flexibility Revealed When Optimizing a Macrocyclic Inhibitor of the Keap1-Nrf2 Protein-Protein Interaction

Author

Begnini, Fabio, Geschwindner, Stefan, Johansson, Patrik, Wissler, Lisa, Lewis, Richard J., Danelius, Emma, Luttens, Andreas, Matricon, Pierre, Carlsson, Jens, Lenders, Stijn, König, Beate, Friedel, Anna, Sjö, Peter, Schiesser, Stefan, Kihlberg, Jan, Begnini, Fabio, Geschwindner, Stefan, Johansson, Patrik, Wissler, Lisa, Lewis, Richard J., Danelius, Emma, Luttens, Andreas, Matricon, Pierre, Carlsson, Jens, Lenders, Stijn, König, Beate, Friedel, Anna, Sjö, Peter, Schiesser, Stefan, and Kihlberg, Jan

Abstract

Upregulation of the transcription factor Nrf2 by inhibition of the interaction with its negative regulator Keap1 constitutes an opportunity for the treatment of disease caused by oxidative stress. We report a structurally unique series of nanomolar Keap1 inhibitors obtained from a natural product-derived macrocyclic lead. Initial exploration of the structure-derived macrocyclic lead. Initial exploration of the structure-activity relationship of the lead, followed by structure-guided optimization, resulted in a 100-fold improvement in inhibitory potency. The macrocyclic core of the nanomolar inhibitors positions three pharmacophore units for productive interactions with key residues of Keap1, including R415, R483, and Y572. Ligand optimization resulted in the displacement of a coordinated water molecule from the Keap1 binding site and a significantly altered thermodynamic profile. In addition, minor reorganizations of R415 and R483 were accompanied by major differences in affinity between ligands. This study therefore indicates the importance of accounting both for the hydration and flexibility of the Keap1 binding site when designing high-affinity ligands.

Published
2022
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