1
|
Zhang L, Li N, Chen Z, Li X, Fan A, Shao H. Investigating the substitution of intermolecular hydrogen bonds on the surface of self-assembled monolayer by scanning electrochemical microscopy. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
2
|
Hassaan E, Hohn C, Ehrmann FR, Goetzke FW, Movsisyan L, Hüfner-Wulsdorf T, Sebastiani M, Härtsch A, Reuter K, Diederich F, Klebe G. Fragment Screening Hit Draws Attention to a Novel Transient Pocket Adjacent to the Recognition Site of the tRNA-Modifying Enzyme TGT. J Med Chem 2020; 63:6802-6820. [PMID: 32515955 DOI: 10.1021/acs.jmedchem.0c00115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fragment-based lead discovery was applied to tRNA-guanine transglycosylase, an enzyme modifying post-transcriptionally tRNAs in Shigella, the causative agent of shigellosis. TGT inhibition prevents translation of Shigella's virulence factor VirF, hence reducing pathogenicity. One discovered fragment opens a transient subpocket in the preQ1-recognition site by pushing back an aspartate residue. This step is associated with reorganization of further amino acids structurally transforming a loop adjacent to the recognition site by duplicating the volume of the preQ1-recognition pocket. We synthesized 6-carboxamido-, 6-hydrazido-, and 4-guanidino-benzimidazoles to target the opened pocket, including a dihydro-imidazoquinazoline with a propyn-1-yl exit vector pointing into the transient pocket and displacing a conserved water network. MD simulations and hydration-site analysis suggest water displacement to contribute favorably to ligand binding. A cysteine residue, exclusively present in bacterial TGTs, serves as gatekeeper of the transient subpocket. It becomes accessible upon pocket opening for selective covalent attachment of electrophilic ligands in eubacterial TGTs.
Collapse
Affiliation(s)
- Engi Hassaan
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Christoph Hohn
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Frederik R Ehrmann
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - F Wieland Goetzke
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Levon Movsisyan
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Tobias Hüfner-Wulsdorf
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Maurice Sebastiani
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Adrian Härtsch
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Klaus Reuter
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - François Diederich
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Gerhard Klebe
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| |
Collapse
|
3
|
Movsisyan LD, Schäfer E, Nguyen A, Ehrmann FR, Schwab A, Rossolini T, Zimmerli D, Wagner B, Daff H, Heine A, Klebe G, Diederich F. Sugar Acetonides are a Superior Motif for Addressing the Large, Solvent-Exposed Ribose-33 Pocket of tRNA-Guanine Transglycosylase. Chemistry 2018; 24:9957-9967. [PMID: 29939431 DOI: 10.1002/chem.201801756] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/10/2018] [Indexed: 11/09/2022]
Abstract
The intestinal disease shigellosis caused by Shigella bacteria affects over 120 million people annually. There is an urgent demand for new drugs as resistance against common antibiotics emerges. Bacterial tRNA-guanine transglycosylase (TGT) is a druggable target and controls the pathogenicity of Shigella flexneri. We report the synthesis of sugar-functionalized lin-benzoguanines addressing the ribose-33 pocket of TGT from Zymomonas mobilis. Ligand binding was analyzed by isothermal titration calorimetry and X-ray crystallography. Pocket occupancy was optimized by variation of size and protective groups of the sugars. The participation of a polycyclic water-cluster in the recognition of the sugar moiety was revealed. Acetonide-protected ribo- and psicofuranosyl derivatives are highly potent, benefiting from structural rigidity, good solubility, and metabolic stability. We conclude that sugar acetonides have a significant but not yet broadly recognized value in drug development.
Collapse
Affiliation(s)
- Levon D Movsisyan
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Elisabeth Schäfer
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Andreas Nguyen
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany
| | - Frederik R Ehrmann
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany
| | - Anatol Schwab
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Thomas Rossolini
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Daniel Zimmerli
- F. Hoffmann-La Roche Ltd, Discovery Technologies, Bldg 92, 4070, Basel, Switzerland
| | - Björn Wagner
- F. Hoffmann-La Roche Ltd, Discovery Technologies, Bldg 92, 4070, Basel, Switzerland
| | - Hamina Daff
- F. Hoffmann-La Roche Ltd, Discovery Technologies, Bldg 92, 4070, Basel, Switzerland
| | - Andreas Heine
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany
| | - Gerhard Klebe
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany
| | - François Diederich
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| |
Collapse
|
4
|
Ehrmann FR, Stojko J, Metz A, Debaene F, Barandun LJ, Heine A, Diederich F, Cianférani S, Reuter K, Klebe G. Soaking suggests "alternative facts": Only co-crystallization discloses major ligand-induced interface rearrangements of a homodimeric tRNA-binding protein indicating a novel mode-of-inhibition. PLoS One 2017; 12:e0175723. [PMID: 28419165 PMCID: PMC5395182 DOI: 10.1371/journal.pone.0175723] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/30/2017] [Indexed: 01/05/2023] Open
Abstract
For the efficient pathogenesis of Shigella, the causative agent of bacillary dysentery, full functionality of tRNA-guanine transglycosylase (TGT) is mandatory. TGT performs post-transcriptional modifications of tRNAs in the anticodon loop taking impact on virulence development. This suggests TGT as a putative target for selective anti-shigellosis drug therapy. Since bacterial TGT is only functional as homodimer, its activity can be inhibited either by blocking its active site or by preventing dimerization. Recently, we discovered that in some crystal structures obtained by soaking the full conformational adaptation most likely induced in solution upon ligand binding is not displayed. Thus, soaked structures may be misleading and suggest irrelevant binding modes. Accordingly, we re-investigated these complexes by co-crystallization. The obtained structures revealed large conformational rearrangements not visible in the soaked complexes. They result from spatial perturbations in the ribose-34/phosphate-35 recognition pocket and, consequently, an extended loop-helix motif required to prevent access of water molecules into the dimer interface loses its geometric integrity. Thermodynamic profiles of ligand binding in solution indicate favorable entropic contributions to complex formation when large conformational adaptations in the dimer interface are involved. Native MS titration experiments reveal the extent to which the homodimer is destabilized in the presence of each inhibitor. Unexpectedly, one ligand causes a complete rearrangement of subunit packing within the homodimer, never observed in any other TGT crystal structure before. Likely, this novel twisted dimer is catalytically inactive and, therefore, suggests that stabilizing this non-productive subunit arrangement may be used as a further strategy for TGT inhibition.
Collapse
Affiliation(s)
| | - Johann Stojko
- Laboratoire de Spectrométrie de Masse Bio-Organique, Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
| | - Alexander Metz
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - François Debaene
- Laboratoire de Spectrométrie de Masse Bio-Organique, Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
| | | | - Andreas Heine
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | | | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse Bio-Organique, Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
| | - Klaus Reuter
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Gerhard Klebe
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail:
| |
Collapse
|
5
|
Neeb M, Hohn C, Ehrmann FR, Härtsch A, Heine A, Diederich F, Klebe G. Occupying a flat subpocket in a tRNA-modifying enzyme with ordered or disordered side chains: Favorable or unfavorable for binding? Bioorg Med Chem 2016; 24:4900-4910. [DOI: 10.1016/j.bmc.2016.07.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/24/2016] [Indexed: 11/29/2022]
|
6
|
Sayyed DR, Jung SH, Kim MS, Han ET, Park WS, Hong SH, Kim YM, Ha KS. In situ PKA activity assay by selective detection of its catalytic subunit using antibody arrays. BIOCHIP JOURNAL 2016. [DOI: 10.1007/s13206-016-1108-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
7
|
Yuan H, Myers SJ, Wells G, Nicholson KL, Swanger SA, Lyuboslavsky P, Tahirovic YA, Menaldino DS, Ganesh T, Wilson LJ, Liotta DC, Snyder JP, Traynelis SF. Context-dependent GluN2B-selective inhibitors of NMDA receptor function are neuroprotective with minimal side effects. Neuron 2015; 85:1305-1318. [PMID: 25728572 DOI: 10.1016/j.neuron.2015.02.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/12/2015] [Accepted: 01/29/2015] [Indexed: 01/09/2023]
Abstract
Stroke remains a significant problem despite decades of work on neuroprotective strategies. NMDA receptor (NMDAR) antagonists are neuroprotective in preclinical models, but have been clinically unsuccessful, in part due to side effects. Here we describe a prototypical GluN2B-selective antagonist with an IC50 value that is 10-fold more potent at acidic pH 6.9 associated with ischemic tissue compared to pH 7.6, a value close to the pH in healthy brain tissue. This should maximize neuroprotection in ischemic tissue while minimizing on-target side effects associated with NMDAR blockade in noninjured brain regions. We have determined the mechanism underlying pH-dependent inhibition and demonstrate the utility of this approach in vivo. We also identify dicarboxylate dimers as a novel proton sensor in proteins. These results provide insight into the molecular basis of pH-dependent neuroprotective NMDAR block, which could be beneficial in a wide range of neurological insults associated with tissue acidification.
Collapse
Affiliation(s)
- Hongjie Yuan
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | - Scott J Myers
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | - Gordon Wells
- Department of Chemistry, Emory University, Atlanta, GA 30322 USA
| | - Katherine L Nicholson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA.,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Sharon A Swanger
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | | | | | | | - Thota Ganesh
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | | | - Dennis C Liotta
- Department of Chemistry, Emory University, Atlanta, GA 30322 USA
| | - James P Snyder
- Department of Chemistry, Emory University, Atlanta, GA 30322 USA
| | | |
Collapse
|
8
|
Persch E, Dumele O, Diederich F. Molekulare Erkennung in chemischen und biologischen Systemen. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201408487] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
9
|
Persch E, Dumele O, Diederich F. Molecular recognition in chemical and biological systems. Angew Chem Int Ed Engl 2015; 54:3290-327. [PMID: 25630692 DOI: 10.1002/anie.201408487] [Citation(s) in RCA: 424] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Indexed: 12/13/2022]
Abstract
Structure-based ligand design in medicinal chemistry and crop protection relies on the identification and quantification of weak noncovalent interactions and understanding the role of water. Small-molecule and protein structural database searches are important tools to retrieve existing knowledge. Thermodynamic profiling, combined with X-ray structural and computational studies, is the key to elucidate the energetics of the replacement of water by ligands. Biological receptor sites vary greatly in shape, conformational dynamics, and polarity, and require different ligand-design strategies, as shown for various case studies. Interactions between dipoles have become a central theme of molecular recognition. Orthogonal interactions, halogen bonding, and amide⋅⋅⋅π stacking provide new tools for innovative lead optimization. The combination of synthetic models and biological complexation studies is required to gather reliable information on weak noncovalent interactions and the role of water.
Collapse
Affiliation(s)
- Elke Persch
- Laboratorium für Organische Chemie, Departement Chemie und Angewandte Biowissenschaften, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich (Switzerland)
| | | | | |
Collapse
|
10
|
Barandun LJ, Ehrmann FR, Zimmerli D, Immekus F, Giroud M, Grünenfelder C, Schweizer WB, Bernet B, Betz M, Heine A, Klebe G, Diederich F. Replacement of Water Molecules in a Phosphate Binding Site by Furanoside-Appendedlin-Benzoguanine Ligands of tRNA-Guanine Transglycosylase (TGT). Chemistry 2014; 21:126-35. [DOI: 10.1002/chem.201405764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 11/09/2022]
|
11
|
Neeb M, Betz M, Heine A, Barandun LJ, Hohn C, Diederich F, Klebe G. Beyond Affinity: Enthalpy–Entropy Factorization Unravels Complexity of a Flat Structure–Activity Relationship for Inhibition of a tRNA-Modifying Enzyme. J Med Chem 2014; 57:5566-78. [DOI: 10.1021/jm5006868] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manuel Neeb
- Institut
für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg
6, 35032 Marburg, Germany
| | - Michael Betz
- Institut
für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg
6, 35032 Marburg, Germany
| | - Andreas Heine
- Institut
für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg
6, 35032 Marburg, Germany
| | - Luzi Jakob Barandun
- Laboratorium
für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Christoph Hohn
- Laboratorium
für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - François Diederich
- Laboratorium
für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
| | - Gerhard Klebe
- Institut
für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg
6, 35032 Marburg, Germany
| |
Collapse
|
12
|
Neeb M, Czodrowski P, Heine A, Barandun LJ, Hohn C, Diederich F, Klebe G. Chasing protons: how isothermal titration calorimetry, mutagenesis, and pKa calculations trace the locus of charge in ligand binding to a tRNA-binding enzyme. J Med Chem 2014; 57:5554-65. [PMID: 24955548 DOI: 10.1021/jm500401x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Drug molecules should remain uncharged while traveling through the body and crossing membranes and should only adopt charged state upon protein binding, particularly if charge-assisted interactions can be established in deeply buried binding pockets. Such strategy requires careful pKa design and methods to elucidate whether and where protonation-state changes occur. We investigated the protonation inventory in a series of lin-benzoguanines binding to tRNA-guanine transglycosylase, showing pronounced buffer dependency during ITC measurements. Chemical modifications of the parent scaffold along with ITC measurements, pKa calculations, and site-directed mutagenesis allow elucidating the protonation site. The parent scaffold exhibits two guanidine-type portions, both likely candidates for proton uptake. Even mutually compensating effects resulting from proton release of the protein and simultaneous uptake by the ligand can be excluded. Two adjacent aspartates induce a strong pKa shift at the ligand site, resulting in protonation-state transition. Furthermore, an array of two parallel H-bonds avoiding secondary repulsive effects contributes to the high-affinity binding of the lin-benzoguanines.
Collapse
Affiliation(s)
- Manuel Neeb
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg , Marbacher Weg 6, 35032 Marburg, Germany
| | | | | | | | | | | | | |
Collapse
|
13
|
Barandun LJ, Immekus F, Kohler PC, Ritschel T, Heine A, Orlando P, Klebe G, Diederich F. High-affinity inhibitors ofZymomonas mobilistRNA–guanine transglycosylase through convergent optimization. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1798-807. [DOI: 10.1107/s0907444913014509] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/26/2013] [Indexed: 11/11/2022]
|
14
|
Biela I, Tidten-Luksch N, Immekus F, Glinca S, Nguyen TXP, Gerber HD, Heine A, Klebe G, Reuter K. Investigation of specificity determinants in bacterial tRNA-guanine transglycosylase reveals queuine, the substrate of its eucaryotic counterpart, as inhibitor. PLoS One 2013; 8:e64240. [PMID: 23704982 PMCID: PMC3660597 DOI: 10.1371/journal.pone.0064240] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/09/2013] [Indexed: 11/19/2022] Open
Abstract
Bacterial tRNA-guanine transglycosylase (Tgt) catalyses the exchange of the genetically encoded guanine at the wobble position of tRNAs(His,Tyr,Asp,Asn) by the premodified base preQ1, which is further converted to queuine at the tRNA level. As eucaryotes are not able to synthesise queuine de novo but acquire it through their diet, eucaryotic Tgt directly inserts the hypermodified base into the wobble position of the tRNAs mentioned above. Bacterial Tgt is required for the efficient pathogenicity of Shigella sp, the causative agent of bacillary dysentery and, hence, it constitutes a putative target for the rational design of anti-Shigellosis compounds. Since mammalian Tgt is known to be indirectly essential to the conversion of phenylalanine to tyrosine, it is necessary to create substances which only inhibit bacterial but not eucaryotic Tgt. Therefore, it seems of utmost importance to study selectivity-determining features within both types of proteins. Homology models of Caenorhabditis elegans Tgt and human Tgt suggest that the replacement of Cys158 and Val233 in bacterial Tgt (Zymomonas mobilis Tgt numbering) by valine and accordingly glycine in eucaryotic Tgt largely accounts for the different substrate specificities. In the present study we have created mutated variants of Z. mobilis Tgt in order to investigate the impact of a Cys158Val and a Val233Gly exchange on catalytic activity and substrate specificity. Using enzyme kinetics and X-ray crystallography, we gained evidence that the Cys158Val mutation reduces the affinity to preQ1 while leaving the affinity to guanine unaffected. The Val233Gly exchange leads to an enlarged substrate binding pocket, that is necessary to accommodate queuine in a conformation compatible with the intermediately covalently bound tRNA molecule. Contrary to our expectations, we found that a priori queuine is recognised by the binding pocket of bacterial Tgt without, however, being used as a substrate.
Collapse
Affiliation(s)
- Inna Biela
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Naomi Tidten-Luksch
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Florian Immekus
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Serghei Glinca
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | | | - Hans-Dieter Gerber
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Andreas Heine
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Gerhard Klebe
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Klaus Reuter
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| |
Collapse
|
15
|
Immekus F, Barandun LJ, Betz M, Debaene F, Petiot S, Sanglier-Cianferani S, Reuter K, Diederich F, Klebe G. Launching spiking ligands into a protein-protein interface: a promising strategy to destabilize and break interface formation in a tRNA modifying enzyme. ACS Chem Biol 2013; 8:1163-78. [PMID: 23534552 DOI: 10.1021/cb400020b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Apart from competitive active-site inhibition of protein function, perturbance of protein-protein interactions by small molecules in oligodomain enzymes opens new perspectives for innovative therapeutics. tRNA-guanine transglycosylase (TGT), a potential target to treat shigellosis, is active only as the homodimer. Consequently, disruption of the dimer interface by small molecules provides a novel inhibition mode. A special feature of this enzyme is the short distance between active site and rim of the dimer interface. This suggests design of expanded active-site inhibitors decorated with rigid, needle-type substituents to spike into potential hot spots of the interaction interface. Ligands with attached ethinyl-type substituents have been synthesized and characterized by Kd measurements, crystallography, noncovalent mass spectrometry, and computer simulations. In contrast to previously determined crystal structures with nonextended active-site inhibitors, a well-defined loop-helix motif, involved in several contacts across the dimer interface, falls apart and suggests enhanced flexibility once the spiking ligands are bound. Mass spectrometry indicates significant destabilization but not full disruption of the complexed TGT homodimer in solution. As directed interactions of the loop-helix motif obviously do not determine dimer stability, a structurally conserved hydrophobic patch composed of several aromatic amino acids is suggested as interaction hot spot. The residues of this patch reside on a structurally highly conserved helix-turn-helix motif, which remains unaffected by the bound spiking ligands. Nevertheless, it is shielded from solvent access by the loop-helix motif that becomes perturbed upon binding of the spiking ligands, which serves as a possible explanation for reduced interface stability.
Collapse
Affiliation(s)
- Florian Immekus
- Institut für Pharmazeutische
Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Luzi Jakob Barandun
- Laboratorium für Organische
Chemie, ETH Zurich Hönggerberg, HCI, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
| | - Michael Betz
- Institut für Pharmazeutische
Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - François Debaene
- Laboratoire de Spectrométrie de Masse Bio-Organique de Strasbourg, 25, rue Becquerel,
67087 Strasbourg Cedex 2, France
| | - Stéphanie Petiot
- Laboratoire de Spectrométrie de Masse Bio-Organique de Strasbourg, 25, rue Becquerel,
67087 Strasbourg Cedex 2, France
| | - Sarah Sanglier-Cianferani
- Laboratoire de Spectrométrie de Masse Bio-Organique de Strasbourg, 25, rue Becquerel,
67087 Strasbourg Cedex 2, France
| | - Klaus Reuter
- Institut für Pharmazeutische
Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - François Diederich
- Laboratorium für Organische
Chemie, ETH Zurich Hönggerberg, HCI, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
| | - Gerhard Klebe
- Institut für Pharmazeutische
Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| |
Collapse
|
16
|
Barandun LJ, Immekus F, Kohler PC, Tonazzi S, Wagner B, Wendelspiess S, Ritschel T, Heine A, Kansy M, Klebe G, Diederich F. From lin-benzoguanines to lin-benzohypoxanthines as ligands for Zymomonas mobilis tRNA-guanine transglycosylase: replacement of protein-ligand hydrogen bonding by importing water clusters. Chemistry 2012; 18:9246-57. [PMID: 22736391 DOI: 10.1002/chem.201200809] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Indexed: 11/12/2022]
Abstract
The foodborne illness shigellosis is caused by Shigella bacteria that secrete the highly cytotoxic Shiga toxin, which is also formed by the closely related enterohemorrhagic Escherichia coli (EHEC). It has been shown that tRNA-guanine transglycosylase (TGT) is essential for the pathogenicity of Shigella flexneri. Herein, the molecular recognition properties of a guanine binding pocket in Zymomonas mobilis TGT are investigated with a series of lin-benzohypoxanthine- and lin-benzoguanine-based inhibitors that bear substituents to occupy either the ribose-33 or the ribose-34 pocket. The three inhibitor scaffolds differ by the substituent at C(6) being H, NH(2), or NH-alkyl. These differences lead to major changes in the inhibition constants, pK(a) values, and binding modes. Compared to the lin-benzoguanines, with an exocyclic NH(2) at C(6), the lin-benzohypoxanthines without an exocyclic NH(2) group have a weaker affinity as several ionic protein-ligand hydrogen bonds are lost. X-ray cocrystal structure analysis reveals that a new water cluster is imported into the space vacated by the lacking NH(2) group and by a conformational shift of the side chain of catalytic Asp102. In the presence of an N-alkyl group at C(6) in lin-benzoguanine ligands, this water cluster is largely maintained but replacement of one of the water molecules in the cluster leads to a substantial loss in binding affinity. This study provides new insight into the role of water clusters at enzyme active sites and their challenging substitution by ligand parts, a topic of general interest in contemporary structure-based drug design.
Collapse
Affiliation(s)
- Luzi Jakob Barandun
- Laboratorium für Organische Chemie, ETH Zürich, Hönggerberg, HCI, 8093 Zurich, Switzerland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Hall DR, Ngan CH, Zerbe BS, Kozakov D, Vajda S. Hot spot analysis for driving the development of hits into leads in fragment-based drug discovery. J Chem Inf Model 2011; 52:199-209. [PMID: 22145575 DOI: 10.1021/ci200468p] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Fragment-based drug design (FBDD) starts with finding fragment-sized compounds that are highly ligand efficient and can serve as a core moiety for developing high-affinity leads. Although the core-bound structure of a protein facilitates the construction of leads, effective design is far from straightforward. We show that protein mapping, a computational method developed to find binding hot spots and implemented as the FTMap server, provides information that complements the fragment screening results and can drive the evolution of core fragments into larger leads with a minimal loss or, in some cases, even a gain in ligand efficiency. The method places small molecular probes, the size of organic solvents, on a dense grid around the protein and identifies the hot spots as consensus clusters formed by clusters of several probes. The hot spots are ranked based on the number of probe clusters, which predicts the binding propensity of the subsites and hence their importance for drug design. Accordingly, with a single exception the main hot spot identified by FTMap binds the core compound found by fragment screening. The most useful information is provided by the neighboring secondary hot spots, indicating the regions where the core can be extended to increase its affinity. To quantify this information, we calculate the density of probes from mapping, which describes the binding propensity at each point, and show that the change in the correlation between a ligand position and the probe density upon extending or repositioning the core moiety predicts the expected change in ligand efficiency.
Collapse
Affiliation(s)
- David R Hall
- Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, Massachusetts 02215, USA
| | | | | | | | | |
Collapse
|
18
|
Ritschel T, Kohler PC, Neudert G, Heine A, Diederich F, Klebe G. How to replace the residual solvation shell of polar active site residues to achieve nanomolar inhibition of tRNA-guanine transglycosylase. ChemMedChem 2010; 4:2012-23. [PMID: 19894214 DOI: 10.1002/cmdc.200900343] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In a computational and structural study, we investigated a series of 4-substituted lin-benzoguanines that are potent inhibitors of tRNA-guanine transglycosylase (TGT), a putative target for the treatment of shigellosis. At first glance, it appears self-evident that the placement of a positively charged ligand functional group between the carboxylate groups of two adjacent aspartate residues in the glycosylase catalytic center leads to enhanced ligand binding. The concomitant displacement of water molecules that partially solvate the aspartates prior to ligand binding appears to result as a consequence of this. However, the case study presented herein shows that this premise is much too superficial. Placement of a likely positively charged amino group at such a pivotal position, interfering with the residual water solvation shell, is at best cost-neutral compared with the unsubstituted parent ligand not conflicting with the residual water shell. A ligand that orients a hydroxy group in this position shows even decreased binding. Based on the cost-neutral placement of the amino functionality, hydrophobic side chains can now be further attached to fill, with increasing potency, a small hydrophobic pocket remote to the aspartates. Any attempts to cross the pivotal position between both aspartates with nonpolar scaffolds reveals only decreased binding, even though the waters of the residual solvation shell are successfully repelled. This surprising observation fostered a detailed analysis of the role of water molecules involved in the residual solvation of polar active site residues. Their geometry and putative replacement in the binding pocket of TGT has been studied by a comparative database analysis, computational active site mapping, and a series of crystal structure analyses. Furthermore, conformational preferences of attached hydrophobic moieties explain their contribution to a gradual increase in binding affinity.
Collapse
Affiliation(s)
- Tina Ritschel
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | | | | | | | | | | |
Collapse
|
19
|
Ritschel T, Atmanene C, Reuter K, Van Dorsselaer A, Sanglier-Cianferani S, Klebe G. An Integrative Approach Combining Noncovalent Mass Spectrometry, Enzyme Kinetics and X-ray Crystallography to Decipher Tgt Protein-Protein and Protein-RNA Interaction. J Mol Biol 2009; 393:833-47. [DOI: 10.1016/j.jmb.2009.07.040] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 07/06/2009] [Accepted: 07/14/2009] [Indexed: 11/29/2022]
|
20
|
Kohler P, Ritschel T, Schweizer W, Klebe G, Diederich F. High-Affinity Inhibitors of tRNA-Guanine Transglycosylase Replacing the Function of a Structural Water Cluster. Chemistry 2009; 15:10809-17. [DOI: 10.1002/chem.200901270] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|