25 results on '"Mühlethaler, Tobias"'
Search Results
2. Bridging the maytansine and vinca sites: Cryptophycins target β-tubulin’s T5-loop
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Abel, Anne-Catherine, Mühlethaler, Tobias, Dessin, Cedric, Schachtsiek, Thomas, Sammet, Benedikt, Sharpe, Timothy, Steinmetz, Michel O., Sewald, Norbert, and Prota, Andrea E.
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- 2024
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3. Watching the release of a photopharmacological drug from tubulin using time-resolved serial crystallography
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Wranik, Maximilian, Weinert, Tobias, Slavov, Chavdar, Masini, Tiziana, Furrer, Antonia, Gaillard, Natacha, Gioia, Dario, Ferrarotti, Marco, James, Daniel, Glover, Hannah, Carrillo, Melissa, Kekilli, Demet, Stipp, Robin, Skopintsev, Petr, Brünle, Steffen, Mühlethaler, Tobias, Beale, John, Gashi, Dardan, Nass, Karol, Ozerov, Dmitry, Johnson, Philip J. M., Cirelli, Claudio, Bacellar, Camila, Braun, Markus, Wang, Meitian, Dworkowski, Florian, Milne, Chris, Cavalli, Andrea, Wachtveitl, Josef, Steinmetz, Michel O., and Standfuss, Jörg
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- 2023
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4. Filling of a water-free void explains the allosteric regulation of the β1-adrenergic receptor by cholesterol
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Abiko, Layara Akemi, Dias Teixeira, Raphael, Engilberge, Sylvain, Grahl, Anne, Mühlethaler, Tobias, Sharpe, Timothy, and Grzesiek, Stephan
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- 2022
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5. Novel fragment-derived colchicine-site binders as microtubule-destabilizing agents
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de la Roche, Noelia Montel, Mühlethaler, Tobias, Di Martino, Rita Maria Concetta, Ortega, Jose Antonio, Gioia, Dario, Roy, Bibhas, Prota, Andrea E., Steinmetz, Michel O., and Cavalli, Andrea
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- 2022
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6. Strengthening an Intramolecular Non‐Classical Hydrogen Bond to Get in Shape for Binding.
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Varga, Norbert, Smieško, Martin, Jiang, Xiaohua, Jakob, Roman P., Wagner, Beatrice, Mühlethaler, Tobias, Dätwyler, Philipp, Zihlmann, Pascal, Rabbani, Said, Maier, Timm, Schwardt, Oliver, and Ernst, Beat
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ISOTHERMAL titration calorimetry ,HYDROGEN bonding ,PHARMACOKINETICS ,ENTROPY ,MOIETIES (Chemistry) - Abstract
In this research article, we report on the strengthening of a non‐classical hydrogen bond (C−H⋅⋅⋅O) by introducing electron withdrawing groups at the carbon atom. The approach is demonstrated on the example of derivatives of the physiological E‐selectin ligand sialyl Lewisx (1, sLex). Its affinity is mainly due to a beneficial entropy term, which is predominantly caused by the pre‐organization of sLex in its binding conformation. We have shown, that among the elements responsible for the pre‐organization, the stabilization by a non‐classical hydrogen bond between the H−C5 of l‐fucose and the ring oxygen O5 of the neighboring d‐galactose moiety is essential and yields 7.4 kJ mol−1. This effect could be further strengthened by replacing l‐fucose by 6,6,6‐trifluoro‐l‐fucose leading to an improved non‐classical H‐bond of 14.9 kJ mol−1, i.e. an improved pre‐organization in the bioactive conformation. For a series of glycomimetics of sLex (1), this outcome could be confirmed by high field NMR‐shifts of the H−C5Fuc, by X‐ray diffraction analysis of glycomimetics co‐crystallized with E‐selectin as well as by isothermal titration calorimetry. Furthermore, the electron‐withdrawing character of the CF3‐group beneficially influences the pharmacokinetic properties of sLex mimetics. Thus, acid‐stability, a prerequisite for gastrointestinal stability, could be substantially improved. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Crystallization Systems for the High-Resolution Structural Analysis of Tubulin–Ligand Complexes
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Mühlethaler, Tobias, primary, Olieric, Natacha, additional, Ehrhard, Valentin A., additional, Wranik, Maximilian, additional, Standfuss, Jörg, additional, Sharma, Ashwani, additional, Prota, Andrea E., additional, and Steinmetz, Michel O., additional
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- 2022
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8. Direct observation of coherent azobenzene photochemistry
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Standfuss, Jörg, primary, Weinert, Tobias, additional, Wranik, Maximillian, additional, Church, Jonathan, additional, Seidel, Hans Peter, additional, Slavov, Chavdar, additional, Masini, Tiziana, additional, James, Daniel, additional, Glover, Hannah, additional, Carrillo, Melissa, additional, Kekilli, Demet, additional, Stipp, Robin, additional, Skopintsev, Petr, additional, Bruenle, Steffen, additional, Gaillard, Natacha, additional, Furrer, Antonia, additional, Gashi, Dardan, additional, Mühlethaler, Tobias, additional, Beale, John, additional, Nass, Karol, additional, Johnson, Philip, additional, Cirelli, Claudio, additional, Ozerov, Dmitry, additional, Dworkowski, Florian, additional, Bacellar, Camila, additional, Milne, Christopher, additional, Steinmetz, Michel, additional, Wachtveitl, Josef, additional, and Schapiro, Igor, additional
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- 2023
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9. Tetra‐ and Hexavalent Siglec‐8 Ligands Modulate Immune Cell Activation
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Conti, Gabriele, primary, Bärenwaldt, Anne, additional, Rabbani, Said, additional, Mühlethaler, Tobias, additional, Sarcevic, Mirza, additional, Jiang, Xiaohua, additional, Schwardt, Oliver, additional, Ricklin, Daniel, additional, Pieters, Roland J., additional, Läubli, Heinz, additional, and Ernst, Beat, additional
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- 2023
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10. A Structural-Reporter Group to Determine the Core Conformation of Sialyl Lewisx Mimetics
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Wagner, Beatrice, primary, Binder, Florian P. C., additional, Jiang, Xiaohua, additional, Mühlethaler, Tobias, additional, Preston, Roland C., additional, Rabbani, Said, additional, Smieško, Martin, additional, Schwardt, Oliver, additional, and Ernst, Beat, additional
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- 2023
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11. Structural insight into the stabilization of microtubules by taxanes
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Prota, Andrea E, primary, Lucena-Agell, Daniel, additional, Ma, Yuntao, additional, Estevez-Gallego, Juan, additional, Li, Shuo, additional, Bargsten, Katja, additional, Josa-Prado, Fernando, additional, Altmann, Karl-Heinz, additional, Gaillard, Natacha, additional, Kamimura, Shinji, additional, Mühlethaler, Tobias, additional, Gago, Federico, additional, Oliva, Maria A, additional, Steinmetz, Michel O, additional, Fang, Wei-Shuo, additional, and Díaz, J Fernando, additional
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- 2023
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12. Tetra- and Hexavalent Siglec-8 Ligands Modulate Immune Cell Activation
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Chemical Biology and Drug Discovery, Afd Chemical Biology and Drug Discovery, Conti, Gabriele, Bärenwaldt, Anne, Rabbani, Said, Mühlethaler, Tobias, Sarcevic, Mirza, Jiang, Xiaohua, Schwardt, Oliver, Ricklin, Daniel, Pieters, Roland J, Läubli, Heinz, Ernst, Beat, Chemical Biology and Drug Discovery, Afd Chemical Biology and Drug Discovery, Conti, Gabriele, Bärenwaldt, Anne, Rabbani, Said, Mühlethaler, Tobias, Sarcevic, Mirza, Jiang, Xiaohua, Schwardt, Oliver, Ricklin, Daniel, Pieters, Roland J, Läubli, Heinz, and Ernst, Beat
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- 2023
13. Datasets for 'Filling of a water-free void explains the allosteric regulation of the β1-adrenergic receptor by cholesterol'
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Abiko, Layara Akemi, Dias Teixeira, Raphael, Engilberge, Sylvain, Grahl, Anne, Mühlethaler, Tobias, Sharpe, Timothy, and Grzesiek, Stephan
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β1-adrenergic receptor ,cholesterol ,structural biology ,G protein-coupled receptor ,allosteric regulation ,xenon - Abstract
Raw data for the X-ray structure determination of a xenon-derivatized isoprenaline∙β1AR crystal, the xenon atom anomalous maps, NMR spectra, and for the ITC curves presented in the manuscript "Filling of a water-free void explains the allosteric regulation of the β1-adrenergic receptor by cholesterol". The main folder (Xe_isoprenaline_b1AR) contains two subfolders. The coordinate file (.pdb), the hkl file, and the electron density map (.mtz) are placed in the folder "structure". The second folder, “anomalous_map”, contains the anomalous maps (.pha and .map), and the hkl files for the four different crystals evaluated (organized in separate folders for the each crystal 1-4). The images for the 4 crystals are placed in separate folders (images_crystal_1, images_crystal_2, images_crystal_3, and images_crystal_4). The folder “NMR” contains processed 1H-15N TROSY NMR spectra (.DAT files), and full Bruker directories for 1H experiments. The datasets are organized in subfolders named according to the manuscript figures. The folder “ITC” contains the original ITC files (.itc) presented in Figure 4 and supplementary Figure S5 of the manuscript., This work was supported by the Swiss National Science Foundation (Grants CRSK-3_195592 to L.A.A., and 31-149927, 31-173089, 31-201270 to S.G.).
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- 2022
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14. Release of a photopharmacological drug from its protein target captured by time-resolved serial crystallography
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Wranik, Maximilian, primary, Weinert, Tobias, additional, Slavov, Chavdar, additional, Masini, Tiziana, additional, Furrer, Antonia, additional, Gaillard, Natacha, additional, Gioia, Dario, additional, Ferrarotti, Marco, additional, James, Daniel, additional, Glover, Hannah, additional, Carrillo, Melissa, additional, Kekilli, Demet, additional, Stipp, Robin, additional, Skopintsev, Petr, additional, Brünle, Steffen, additional, Mühlethaler, Tobias, additional, Beale, John, additional, Gashi, Dardan, additional, Nass, Karol, additional, Ozerov, Dmitry, additional, Johnson, Philip, additional, Cirelli, Claudio, additional, Bacellar, Camila, additional, Braun, Markus, additional, Wang, Meitian, additional, Dworkowski, Florian, additional, Milne, Christopher, additional, Cavalli, Andrea, additional, Wachtveitl, Josef, additional, Steinmetz, Michel, additional, and Standfuss, Jörg, additional
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- 2022
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15. Potent neutralization by monoclonal human IgM against SARS‐CoV‐2 is impaired by class switch
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Callegari, Ilaria, primary, Schneider, Mika, additional, Berloffa, Giuliano, additional, Mühlethaler, Tobias, additional, Holdermann, Sebastian, additional, Galli, Edoardo, additional, Roloff, Tim, additional, Boss, Renate, additional, Infanti, Laura, additional, Khanna, Nina, additional, Egli, Adrian, additional, Buser, Andreas, additional, Zimmer, Gert, additional, Derfuss, Tobias, additional, and Sanderson, Nicholas S R, additional
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- 2022
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16. A Structural-Reporter Group to Determine the Core Conformation of Sialyl Lewis x Mimetics.
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Wagner, Beatrice, Binder, Florian P. C., Jiang, Xiaohua, Mühlethaler, Tobias, Preston, Roland C., Rabbani, Said, Smieško, Martin, Schwardt, Oliver, and Ernst, Beat
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SPATIAL orientation ,FUCOSE ,MOIETIES (Chemistry) ,GALACTOSE - Abstract
The d-GlcNAc moiety in sialyl Lewis
x (sLex , 1) acts predominantly as a linker to position the d-Gal and the l-Fuc moieties in the bioactive spatial orientation. The hypothesis has been made that the NHAc group of GlcNAc pushes the fucose underneath the galactose and, thus, contributes to the stabilization of the bioactive conformation of the core of sLex (1). To test this hypothesis, GlcNAc mimetics consisting of (R,R)-1,2-cyclohexanediols substituted with alkyl and aryl substituents adjacent to the linking position of the fucose moiety were synthesized. To explore a broad range of extended and spatially demanding R-groups, an enzymatic approach for the synthesis of 3-alkyl/aryl-1,2-cyclohexanediols (3b-n) was applied. These cyclohexanediol derivatives were incorporated into the sLex mimetics 2b-n. For analyzing the relationship of affinity and core conformation, a1 H NMR structural-reporter-group concept was applied. Thus, the chemical shift of H-C5Fuc proved to be a sensitive indicator for the degree of pre-organization of the core of this class of sLex mimetics and therefore could be used to quantify the contribution of the R-groups. [ABSTRACT FROM AUTHOR]- Published
- 2023
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17. Rational Design of a Novel Tubulin Inhibitor with a Unique Mechanism of Action
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Mühlethaler, Tobias, primary, Milanos, Lampros, additional, Ortega, Jose Antonio, additional, Blum, Thorsten B., additional, Gioia, Dario, additional, Roy, Bibhas, additional, Prota, Andrea E., additional, Cavalli, Andrea, additional, and Steinmetz, Michel O., additional
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- 2022
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18. Molecular snapshots of drug release from tubulin over eleven orders of magnitude in time
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Wranik, Maximillian, primary, Weinert, Tobias, additional, Slavov, Chavdar, additional, Masini, Tiziana, additional, Furrer, Antonia, additional, Gaillard, Natacha, additional, Gioia, Dario, additional, Ferrarotti, Marco, additional, James, Daniel, additional, Glover, Hannah, additional, Carrillo, Melissa, additional, Kekilli, Demet, additional, Stipp, Robin, additional, Skopintsev, Petr, additional, Brünle, Steffen, additional, Mühlethaler, Tobias, additional, Beale, John, additional, Gashi, Dardan, additional, Nass, Karol, additional, Ozerov, Dmitry, additional, Johnson, Philip J.M., additional, Cirelli, Claudio, additional, Bacellar, Camila, additional, Braun, Markus, additional, Wang, Meitian, additional, Dworkowski, Florian, additional, Milne, Chris, additional, Cavalli, Andrea, additional, Wachtveitl, Josef, additional, Steinmetz, Michel O., additional, and Standfuss, Jörg, additional
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- 2022
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19. Comprehensive analysis of binding sites in tubulin to develop small molecule ligands
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Mühlethaler, Tobias, Steinmetz, Michel, Maier, Timm, and Glockshuber, Rudolf
- Abstract
In eukaryotic cells, microtubules are highly dynamic filaments of the cytoskeleton where they are involved in vital tasks like cell division, intracellular transport, and cell polarization. Microtubules are assembled from their building block tubulin, and both microtubules and tubulin are known to bind a multitude of regulators. In cells, protein partners bind to microtubules to either modulate their behavior or to use them to fulfill various cellular functions. In addition to proteins, several dozen small molecule ligands are known to influence microtubule dynamics and they target six distinct binding sites on tubulin. As tumor cells exhibit faster rates of cell division than healthy cells, it is not surprising that mitotic inhibition is one of the many strategies to treat cancer. Indeed, five of these ligands are currently used in the clinic as monotherapeutic antitubulin drugs. While their mechanism of action differ, all original ligands are derived from natural sources and have complex chemical structures. Based on these observations, we aimed in the present thesis to address the two outstanding open questions whether there are additional binding sites present in tubulin and if it is possible to develop a small molecule ligand targeting microtubules. To tackle these two questions, we first performed an X-ray crystallography based fragment screen. Using this approach, we found 56 chemically diverse fragments that bound to 10 distinct binding sites on tubulin. Moreover, we combined a computational binding-site search with the results from our fragment screen to comprehensively map all binding sites in tubulin. Indeed, we found 18 novel sites that are not targeted by any of the known ligands. Out of these, 11 sites are also not targeted by any known tubulin protein partner. These findings demonstrate that our combined computational and crystallographic approach is a powerful tool to map binding sites in any protein for which a well diffracting crystal system is available. With the structural information at hands on a plethora of new fragments bound to tubulin, we went on to develop novel small molecule ligands targeting tubulin. As a first step and proof of principle, we chose a fragment that binds to the well-known colchicine site and has structural resemblance to nocodazole, a microtubule-destabilizing agent that was proven to be too toxic to use in the clinic. This fragment establishes an intricate interaction network with tubulin, consisting of four hydrogen bonds. Indeed, when probing for the importance of these hydrogen bonds by removing them individually we learned that all of them are necessary to retain binding. While leaving the interaction network unchanged, we still had the option to grow our fragment by attaching continuously larger substitutions and in this way, we managed to improve our fragment from an IC50 of 54 μM to a final IC50 of 0.94 μM in our best compound. These results demonstrate that already a small fragment can exhibit optimal interactions to its target and that indeed our fragment hits can be used to obtain potent tubulin inhibitors. As our pilot project showed that our fragments can be improved, we went on to apply our freshly gained insight to a novel tubulin-binding site. This time we chose a fragment linking strategy, in which several fragments that bind close to each other are combined. First, we took a fragment that contained a common binding motif as a starting point to gain specificity. Second, we looked for additional fragments binding in close proximity that could be chemically linked to our starting fragment. The two additional fragments that we selected suggested that expanding our starting fragment with a phenyl moiety should increase its affinity. Indeed, with our linking effort we obtained a first ligand with an IC50 of 48 μM, whereas none of the starting fragments showed any effect on cells. Additional rounds of modification of this first ligand brought us our most potent compound, which we named Todalam. Todalam has an IC50 value of 8.8 μM and showed microtubule depolymerizing effects in vitro as well as in cells. Furthermore, we proposed a novel, twofold mechanism of action for Todalam: First, Todalam acts like a “plug” locking tubulin in its curved conformation and second, it links free tubulin to ring like structures that are incompatible with microtubule assembly. This is to the best of our knowledge the first rationally designed tubulin-targeting agent with a novel binding site and a novel molecular mechanism of action. Overall, we demonstrated that crystallographic fragment screening is a very powerful tool both for finding novel binding sites as well as for developing small molecule ligands. Our results set a basis for future ligand design efforts by providing a diverse set of novel tubulin-binding sites and ligands. They further offer two lead-like compounds that are ready to be developed into small lead molecules.
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- 2022
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20. Prodrugs of E‐selectin Antagonists with Enhanced Pharmacokinetic Properties
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Dätwyler, Philipp, primary, Jiang, Xiaohua, additional, Wagner, Beatrice, additional, Varga, Norbert, additional, Mühlethaler, Tobias, additional, Hostettler, Katja, additional, Rabbani, Said, additional, Schwardt, Oliver, additional, and Ernst, Beat, additional
- Published
- 2021
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21. Prodrugs of E‐selectin Antagonists with Enhanced Pharmacokinetic Properties.
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Dätwyler, Philipp, Jiang, Xiaohua, Wagner, Beatrice, Varga, Norbert, Mühlethaler, Tobias, Hostettler, Katja, Rabbani, Said, Schwardt, Oliver, and Ernst, Beat
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- 2022
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22. Structural insight into the stabilization of microtubules by taxanes
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Andrea E Prota, Daniel Lucena-Agell, Yuntao Ma, Juan Estevez-Gallego, Shuo Li, Katja Bargsten, Fernando Josa-Prado, Karl-Heinz Altmann, Natacha Gaillard, Shinji Kamimura, Tobias Mühlethaler, Federico Gago, Maria A Oliva, Michel O Steinmetz, Wei-Shuo Fang, J Fernando Díaz, Ministerio de Ciencia e Innovación (España), Consejo Superior de Investigaciones Científicas (España), Fundación Tatiana Pérez de Guzmán el Bueno, European Commission, Swiss National Science Foundation, Japan Society for the Promotion of Science, National Natural Science Foundation of China, Chinese Academy of Medical Sciences, Prota, Andrea E., Lucena-Agell, Daniel, Estévez-Gallego, Juan, Josa-Prado, Fernando, Altmann, Karl-Heinz, Gaillard, Natacha, Kamimura, Shinji, Mühlethaler, Tobias, Gago, Federico, Oliva, María A., Steinmetz, Michel O., and Díaz, José Fernando
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General Immunology and Microbiology ,General Neuroscience ,General Medicine ,General Biochemistry, Genetics and Molecular Biology - Abstract
35 p.-12 fig.-2 tab.-3 animat.-1 schem.This article is dedicated to the memory of Dr Linda Amos, a dear friend and pioneer in the study of microtubules and the mechanism of action of paclitaxel (Amos and Löwe, 1999), who passed away while we were assembling this manuscript., Paclitaxel (Taxol) is a taxane and a chemotherapeutic drug that stabilizes microtubules. While the interaction of paclitaxel with microtubules is well described, the lack of high-resolution structural information on a tubulin-taxane complex precludes a comprehensive description of the binding determinants that affect its mechanism of action. Here, we solved the crystal structure of baccatin III the core moiety of paclitaxel-tubulin complex at 1.9 Å resolution. Based on this information, we engineered taxanes with modified C13 side chains, solved their crystal structures in complex with tubulin, and analyzed their effects on microtubules (X-ray fiber diffraction), along with those of paclitaxel, docetaxel, and baccatin III. Further comparison of high-resolution structures and microtubules’ diffractions with the apo forms and molecular dynamics approaches allowed us to understand the consequences of taxane binding to tubulin in solution and under assembled conditions. The results sheds light on three main mechanistic questions: (1) taxanes bind better to microtubules than to tubulin because tubulin assembly is linked to a βM-loopconformational reorganization (otherwise occludes the access to the taxane site) and, bulky C13 side chains preferentially recognize the assembled conformational state; (2) the occupancy of the taxane site has no influence on the straightness of tubulin protofilaments and; (3) longitudinal expansion of the microtubule lattices arises from the accommodation of the taxane core within the site, a process that is no related to the microtubule stabilization (baccatin III is biochemically inactive). In conclusion, our combined experimental and computational approach allowed us to describe the tubulin-taxane interaction in atomic detail and assess the structural determinants for binding., Ministerio de Ciencia e Innovación (PID2019-104545RB-I00 (AEI/10.13039/501100011033)) J Fernando Díaz Consejo Superior de Investigaciones Científicas (PIE 201920E111) J Fernando Díaz Fundación Tatiana Pérez de Guzmán el Bueno (Proyecto de Investigación en Neurociencia 2020) J Fernando Díaz European Union NextGenerationEU (H2020-MSCA-ITN-2019 860070 TUBINTRAIN) Andrea E Prota J Fernando Díaz Swiss National Science Foundation (310030_192566) Michel O Steinmetz JSPS KAKENHI (16K07328/17H03668) Shinji Kamimura National Natural Science Foundation of China (30930108) Wei-Shuo Fang Chinese Academy of Medical Sciences (2016-I2M-1-010) Wei-Shuo Fang Ministerio de Ciencia e Innovación (PID2019-104070RB-C22 (AEI/10.13039/501100011033)) Federico Gago We thank Ganadería Fernando Díaz for calf brains supply and staff of beamlines X06DA of the Swiss Light Source (Paul Scherrer Institut, Villigen PSI, Switzerland) and BL11-NDC-SWEET (ALBA, Cerdanyola del Vallès, Spain) for their support. We also thank Mr Pedro Gascón Blanco for his private donation to the project to support a month of a student salary.
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- 2023
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23. Tetra- and Hexavalent Siglec-8 Ligands Modulate Immune Cell Activation.
- Author
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Conti G, Bärenwaldt A, Rabbani S, Mühlethaler T, Sarcevic M, Jiang X, Schwardt O, Ricklin D, Pieters RJ, Läubli H, and Ernst B
- Subjects
- Ligands, Sialic Acid Binding Immunoglobulin-like Lectins metabolism, Polysaccharides chemistry, Eosinophils metabolism
- Abstract
Carbohydrate-binding proteins are generally characterized by poor affinities for their natural glycan ligands, predominantly due to the shallow and solvent-exposed binding sites. To overcome this drawback, nature has exploited multivalency to strengthen the binding by establishing multiple interactions simultaneously. The development of oligovalent structures frequently proved to be successful, not only for proteins with multiple binding sites, but also for proteins that possess a single recognition domain. Herein we present the syntheses of a number of oligovalent ligands for Siglec-8, a monomeric I-type lectin found on eosinophils and mast cells, alongside the thermodynamic characterization of their binding. While the enthalpic contribution of each binding epitope was within a narrow range to that of the monomeric ligand, the entropy penalty increased steadily with growing valency. Additionally, we observed a successful agonistic binding of the tetra- and hexavalent and, to an even larger extent, multivalent ligands to Siglec-8 on immune cells and modulation of immune cell activation. Thus, triggering a biological effect is not restricted to multivalent ligands but could be induced by low oligovalent ligands as well, whereas a monovalent ligand, despite binding with similar affinity, showed an antagonistic effect., (© 2023 Wiley-VCH GmbH.)
- Published
- 2023
- Full Text
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24. Rational Design of a Novel Tubulin Inhibitor with a Unique Mechanism of Action.
- Author
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Mühlethaler T, Milanos L, Ortega JA, Blum TB, Gioia D, Roy B, Prota AE, Cavalli A, and Steinmetz MO
- Subjects
- Cell Death, Microtubules metabolism, Protein Binding, Tubulin chemistry, Tubulin Modulators chemistry
- Abstract
In this study, we capitalized on our previously performed crystallographic fragment screen and developed the antitubulin small molecule Todalam with only two rounds of straightforward chemical synthesis. Todalam binds to a novel tubulin site, disrupts microtubule networks in cells, arrests cells in G2/M, induces cell death, and synergizes with vinblastine. The compound destabilizes microtubules by acting as a molecular plug that sterically inhibits the curved-to-straight conformational switch in the α-tubulin subunit, and by sequestering tubulin dimers into assembly incompetent oligomers. Our results describe for the first time the generation of a fully rationally designed small molecule tubulin inhibitor from a fragment, which displays a unique molecular mechanism of action. They thus demonstrate the usefulness of tubulin-binding fragments as valuable starting points for innovative antitubulin drug and chemical probe discovery campaigns., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
- Published
- 2022
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25. Preclinical and Early Clinical Development of PTC596, a Novel Small-Molecule Tubulin-Binding Agent.
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Jernigan F, Branstrom A, Baird JD, Cao L, Dali M, Furia B, Kim MJ, O'Keefe K, Kong R, Laskin OL, Colacino JM, Pykett M, Mollin A, Sheedy J, Dumble M, Moon YC, Sheridan R, Mühlethaler T, Spiegel RJ, Prota AE, Steinmetz MO, and Weetall M
- Subjects
- Adult, Aged, Aged, 80 and over, Animals, Apoptosis, Benzimidazoles pharmacokinetics, Cell Proliferation, Female, Glioblastoma pathology, Humans, Leiomyosarcoma pathology, Male, Maximum Tolerated Dose, Mice, Mice, Nude, Middle Aged, Prognosis, Pyrazines pharmacokinetics, Tissue Distribution, Tubulin Modulators pharmacokinetics, Tumor Cells, Cultured, Xenograft Model Antitumor Assays, Benzimidazoles pharmacology, Glioblastoma drug therapy, Leiomyosarcoma drug therapy, Pyrazines pharmacology, Tubulin Modulators pharmacology
- Abstract
PTC596 is an investigational small-molecule tubulin-binding agent. Unlike other tubulin-binding agents, PTC596 is orally bioavailable and is not a P-glycoprotein substrate. So as to characterize PTC596 to position the molecule for optimal clinical development, the interactions of PTC596 with tubulin using crystallography, its spectrum of preclinical in vitro anticancer activity, and its pharmacokinetic-pharmacodynamic relationship were investigated for efficacy in multiple preclinical mouse models of leiomyosarcomas and glioblastoma. Using X-ray crystallography, it was determined that PTC596 binds to the colchicine site of tubulin with unique key interactions. PTC596 exhibited broad-spectrum anticancer activity. PTC596 showed efficacy as monotherapy and additive or synergistic efficacy in combinations in mouse models of leiomyosarcomas and glioblastoma. PTC596 demonstrated efficacy in an orthotopic model of glioblastoma under conditions where temozolomide was inactive. In a first-in-human phase I clinical trial in patients with cancer, PTC596 monotherapy drug exposures were compared with those predicted to be efficacious based on mouse models. PTC596 is currently being tested in combination with dacarbazine in a clinical trial in adults with leiomyosarcoma and in combination with radiation in a clinical trial in children with diffuse intrinsic pontine glioma., (©2021 The Authors; Published by the American Association for Cancer Research.)
- Published
- 2021
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- View/download PDF
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