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Díaz-Rullo J, González-Pastor JE. tRNA queuosine modification is involved in biofilm formation and virulence in bacteria. Nucleic Acids Res 2023; 51:9821-9837. [PMID: 37638766 PMCID: PMC10570037 DOI: 10.1093/nar/gkad667] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/27/2023] [Accepted: 08/11/2023] [Indexed: 08/29/2023] Open
Abstract
tRNA modifications are crucial for fine-tuning of protein translation. Queuosine (Q) modification of tRNAs is thought to modulate the translation rate of NAU codons, but its physiological role remains elusive. Therefore, we hypothesize that Q-tRNAs control those physiological processes involving NAU codon-enriched genes (Q-genes). Here, we report a novel bioinformatic strategy to predict Q-genes, revealing a widespread enrichment in functions, especially those related to biofilm formation and virulence in bacteria, and particularly in human pathogens. Indeed, we experimentally verified that these processes were significantly affected by altering the degree of tRNA Q-modification in different model bacteria, representing the first report of a general mechanism controlling biofilm formation and virulence in Gram-positive and Gram-negative bacteria possibly through the coordination of the expression of functionally related genes. Furthermore, we propose that changes in Q availability in a microbiome would affect its functionality. Our findings open the door to the control of bacterial infections and biofilm formation by inhibition of tRNA Q-modification.
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Affiliation(s)
- Jorge Díaz-Rullo
- Department of Molecular Evolution, Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir km 4, Torrejón de Ardoz 28850, Madrid, Spain
| | - José Eduardo González-Pastor
- Department of Molecular Evolution, Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir km 4, Torrejón de Ardoz 28850, Madrid, Spain
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2
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Wang Z, Ma J, Wang T, Qin C, Hu X, Mosa A, Ling W. Environmental health risks induced by interaction between phthalic acid esters (PAEs) and biological macromolecules: A review. CHEMOSPHERE 2023; 328:138578. [PMID: 37023900 DOI: 10.1016/j.chemosphere.2023.138578] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/19/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
As a kind of compounds abused in industry productions, phthalic acid esters (PAEs) cause serious problems in natural environment. PAEs pollution has penetrated into environmental media and human food chain. This review consolidates the updated information to assess the occurrence and distribution of PAEs in each transmission section. It is found that micrograms per kilogram of PAEs are exposed to humans through daily diets. After entering the human body, PAEs often undergo the metabolic process of hydrolysis to monoesters phthalates and conjugation process. Unfortunately, in the process of systemic circulation, PAEs will interact with biological macromolecules in vivo under the action of non-covalent binding, which is also the essence of biological toxicity. The interactions usually operate in the following pathways: (a) competitive binding; (b) functional interference; and (c) abnormal signal transduction. While the non-covalent binding forces mainly contain hydrophobic interaction, hydrogen bond, electrostatic interaction, and π interaction. As a typical endocrine disruptor, the health risks of PAEs often start with endocrine disorder, further leading to metabolic disruption, reproductive disorders, and nerve injury. Besides, genotoxicity and carcinogenicity are also attributed to the interaction between PAEs and genetic materials. This review also pointed out that the molecular mechanism study on biological toxicity of PAEs are deficient. Future toxicological research should pay more attention to the intermolecular interactions. This will be beneficial for evaluating and predicting the biological toxicity of pollutants at molecular scale.
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Affiliation(s)
- Zeming Wang
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Junchao Ma
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Tingting Wang
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Chao Qin
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Xiaojie Hu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Ahmed Mosa
- Soils Department, Faculty of Agriculture, Mansoura University, 35516, Mansoura, Egypt
| | - Wanting Ling
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
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3
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Irving CD, Floreancig JT, Gasonoo M, Kelley AS, Laulhé S. Synthesis of Imide and Amine Derivatives via Deoxyamination of Alcohols Using
N
‐Haloimides and Triphenylphosphine. ChemistrySelect 2021; 6:8874-8878. [DOI: 10.1002/slct.202102296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Charles D. Irving
- Department of Chemistry and Chemical Biology Indiana University-Purdue University Indianapolis Indianapolis IN 46202 United States
| | - Jack T. Floreancig
- Department of Chemistry and Chemical Biology Indiana University-Purdue University Indianapolis Indianapolis IN 46202 United States
| | - Makafui Gasonoo
- Department of Chemistry and Chemical Biology Indiana University-Purdue University Indianapolis Indianapolis IN 46202 United States
| | - Alexandra S. Kelley
- Department of Chemistry and Chemical Biology Indiana University-Purdue University Indianapolis Indianapolis IN 46202 United States
| | - Sébastien Laulhé
- Department of Chemistry and Chemical Biology Indiana University-Purdue University Indianapolis Indianapolis IN 46202 United States
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4
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Uncertainty in protein-ligand binding constants: asymmetric confidence intervals versus standard errors. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:661-670. [PMID: 33837826 DOI: 10.1007/s00249-021-01518-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/05/2021] [Accepted: 03/13/2021] [Indexed: 01/18/2023]
Abstract
Equilibrium binding constants (Kb) between chemical compounds and target proteins or between interacting proteins provide a quantitative understanding of biological interaction mechanisms. Reported uncertainties of measured experimental parameters are critical for decision-making in many scientific areas, e.g., in lead compound discovery processes and in comparing computational predictions with experimental results. Uncertainties in measured Kb values are commonly represented by a symmetric normal distribution, often quoted in terms of the experimental value plus-minus the standard deviation. However, in general, the distributions of measured Kb (and equivalent Kd) values and the corresponding free energy change ΔGb are all asymmetric to varying degree. Here, using a simulation approach, we illustrate the effect of asymmetric Kb distributions within the realm of isothermal titration calorimetry (ITC) experiments. Further we illustrate the known, but perhaps not widely appreciated, fact that when distributions of any of Kb, Kd and ΔGb are transformed into each other, their degree of asymmetry is changed. Consequently, we recommend that a more accurate way of expressing the uncertainties of Kb, Kd, and ΔGb values is to consistently report 95% confidence intervals, in line with other authors' suggestions. The ways to obtain such error ranges are discussed in detail and exemplified for a binding reaction obtained by ITC.
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5
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Queuine Is a Nutritional Regulator of Entamoeba histolytica Response to Oxidative Stress and a Virulence Attenuator. mBio 2021; 12:mBio.03549-20. [PMID: 33688012 PMCID: PMC8092309 DOI: 10.1128/mbio.03549-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Entamoeba histolytica is a unicellular parasite that causes amebiasis. The parasite resides in the colon and feeds on the colonic microbiota. Queuosine is a naturally occurring modified ribonucleoside found in the first position of the anticodon of the transfer RNAs for Asp, Asn, His, and Tyr. Eukaryotes lack pathways to synthesize queuine, the nucleobase precursor to queuosine, and must obtain it from diet or gut microbiota. Here, we describe the effects of queuine on the physiology of the eukaryotic parasite Entamoeba histolytica, the causative agent of amebic dysentery. Queuine is efficiently incorporated into E. histolytica tRNAs by a tRNA-guanine transglycosylase (EhTGT) and this incorporation stimulates the methylation of C38 in
tRNAGUCAsp. Queuine protects the parasite against oxidative stress (OS) and antagonizes the negative effect that oxidation has on translation by inducing the expression of genes involved in the OS response, such as heat shock protein 70 (Hsp70), antioxidant enzymes, and enzymes involved in DNA repair. On the other hand, queuine impairs E. histolytica virulence by downregulating the expression of genes previously associated with virulence, including cysteine proteases, cytoskeletal proteins, and small GTPases. Silencing of EhTGT prevents incorporation of queuine into tRNAs and strongly impairs methylation of C38 in
tRNAGUCAsp, parasite growth, resistance to OS, and cytopathic activity. Overall, our data reveal that queuine plays a dual role in promoting OS resistance and reducing parasite virulence.
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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.
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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
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Zhang J, Chen L, Dong Y, Yang J, Wu Y. A Cu 2O/TBAB-promoted approach to synthesize heteroaromatic 2-amines via one-pot cyclization of aryl isothiocyanates with ortho-substituted amines in water. Org Biomol Chem 2020; 18:7425-7430. [PMID: 32936165 DOI: 10.1039/d0ob01431a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient approach to synthesize heteroaromatic 2-amines from one-pot desulfurization/dehydrogenative cyclization of aryl isothiocyanates with ortho-substituted amines in water was developed. This approach tolerated a wide range of functional groups on the aromatic ring, providing a practical and environment-friendly process to synthesize heteroaromatic 2-amines in moderate to excellent yields. A plausible mechanism was proposed and the role of TBAB and Cu2O in the present strategy was suggested with the help of ESI mass spectrometry.
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Affiliation(s)
- Jinli Zhang
- Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou, 450052, P.R. China. and College of Chemistry, Green Catalytic Center, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Ling Chen
- Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou, 450052, P.R. China.
| | - Yibo Dong
- Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou, 450052, P.R. China.
| | - Jinchen Yang
- College of Chemistry, Green Catalytic Center, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Yangjie Wu
- Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou, 450052, P.R. China. and College of Chemistry, Green Catalytic Center, Zhengzhou University, Zhengzhou 450001, P. R. China
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8
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Gofton AW, Margos G, Fingerle V, Hepner S, Loh SM, Ryan U, Irwin P, Oskam CL. Genome-wide analysis of Borrelia turcica and 'Candidatus Borrelia tachyglossi' shows relapsing fever-like genomes with unique genomic links to Lyme disease Borrelia. INFECTION GENETICS AND EVOLUTION 2018; 66:72-81. [PMID: 30240834 DOI: 10.1016/j.meegid.2018.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/16/2018] [Accepted: 09/16/2018] [Indexed: 02/08/2023]
Abstract
Borrelia are tick-borne bacteria that in humans are the aetiological agents of Lyme disease and relapsing fever. Here we present the first genomes of B. turcica and B. tachyglossi, members of a recently described and rapidly expanding Borrelia clade associated with reptile (B. turcica) or echidna (B. tachyglossi) hosts, transmitted by hard ticks, and of unknown pathogenicity. Borrelia tachyglossi and B. turcica genomes are similar to those of relapsing fever Borrelia species, containing a linear ~ 900 kb chromosome, a single long (> 70 kb) linear plasmid, and numerous short (< 40 kb) linear and circular plasmids, as well as a suite of housekeeping and macronutrient biosynthesis genes which are not found in Lyme disease Borrelia. Additionally, both B. tachyglossi and B. turcica contain paralogous vsp and vlp proteins homologous to those used in the multiphasic antigen-switching system used by relapsing fever Borrelia to evade vertebrate immune responses, although their number was greatly reduced compared to human-infectious species. However, B. tachyglossi and B. turcica chromosomes also contain numerous genes orthologous to Lyme disease Borrelia-specific genes, demonstrating a unique evolutionary, and potentially phenotypic link between these groups. Borrelia tachyglossi and B. turcica genomes also have unique genetic features, including degraded and deleted tRNA modification genes, and an expanded range of macronutrient salvage and biosynthesis genes compared to relapsing fever and Lyme disease Borrelia. These genomes and genomic comparisons provide an insight into the biology and evolutionary origin of these Borrelia, and provide a valuable resource for future work.
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Affiliation(s)
- Alexander W Gofton
- The Vector and Water-Borne Pathogen Research Group, The School of Veterinary and Life Sciences, Murdoch University, Perth 6150, Australia; Present address: Australian National Insect Collection, CSIRO, Black Mountain, Canberra 2601, Australia.
| | - Gabriele Margos
- German National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, Oberschleissheim, 85764, Germany
| | - Volker Fingerle
- German National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, Oberschleissheim, 85764, Germany
| | - Sabrina Hepner
- German National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, Oberschleissheim, 85764, Germany
| | - Siew-May Loh
- The Vector and Water-Borne Pathogen Research Group, The School of Veterinary and Life Sciences, Murdoch University, Perth 6150, Australia
| | - Una Ryan
- The Vector and Water-Borne Pathogen Research Group, The School of Veterinary and Life Sciences, Murdoch University, Perth 6150, Australia
| | - Peter Irwin
- The Vector and Water-Borne Pathogen Research Group, The School of Veterinary and Life Sciences, Murdoch University, Perth 6150, Australia
| | - Charlotte L Oskam
- The Vector and Water-Borne Pathogen Research Group, The School of Veterinary and Life Sciences, Murdoch University, Perth 6150, Australia
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9
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Yamaotsu N, Hirono S. In silico fragment-mapping method: a new tool for fragment-based/structure-based drug discovery. J Comput Aided Mol Des 2018; 32:1229-1245. [PMID: 30196523 DOI: 10.1007/s10822-018-0160-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/04/2018] [Indexed: 01/09/2023]
Abstract
Here, we propose an in silico fragment-mapping method as a potential tool for fragment-based/structure-based drug discovery (FBDD/SBDD). For this method, we created a database named Canonical Subsite-Fragment DataBase (CSFDB) and developed a knowledge-based fragment-mapping program, Fsubsite. CSFDB consists of various pairs of subsite-fragments derived from X-ray crystal structures of known protein-ligand complexes. Using three-dimensional similarity-matching between subsites on one protein and another, Fsubsite compares the surface of a target protein with all subsites in CSFDB. When a local topography similar to the subsite is found on the surface, Fsubsite places a fragment combined with the subsite in CSFDB on the target protein. For validation purposes, we applied the method to the apo-structure of cyclin-dependent kinase 2 (CDK2) and identified four compounds containing three mapped fragments that existed in the list of known inhibitors of CDK2. Next, the utility of our fragment-mapping method for fragment-growing was examined on the complex structure of tRNA-guanine transglycosylase with a small ligand. Fsubsite mapped appropriate fragments on the same position as the binding ligand or in the vicinity of the ligand. Finally, a 3D-pharmacophore model was constructed from the fragments mapped on the apo-structure of heat shock protein 90-α (HSP90α). Then, 3D pharmacophore-based virtual screening was carried out using a commercially available compound database. The resultant hit compounds were very similar to a known ligand of HSP90α. As a result of these findings, this in silico fragment-mapping method seems to be a useful tool for computational FBDD and SBDD.
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Affiliation(s)
- Noriyuki Yamaotsu
- Department of Pharmaceutical Sciences, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan.
| | - Shuichi Hirono
- Department of Pharmaceutical Sciences, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan.
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10
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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.
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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
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11
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Sales ZS, Mani NS, Allison BD. The synthesis of 2-amino-4(3H)-quinazolinones and related heterocycles via a mild electrocyclization of aryl guanidines. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.03.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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12
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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.
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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:
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13
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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]
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14
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Hohn C, Härtsch A, Ehrmann FR, Pfaffeneder T, Trapp N, Dumele O, Klebe G, Diederich F. An Immucillin-Based Transition-State-Analogous Inhibitor of tRNA-Guanine Transglycosylase (TGT). Chemistry 2016; 22:6750-4. [PMID: 26991861 DOI: 10.1002/chem.201600883] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Indexed: 11/06/2022]
Abstract
Shigellosis is one of the most severe diarrheal diseases worldwide without any efficient treatment so far. The enzyme tRNA-guanine transglycosylase (TGT) has been identified as a promising target for small-molecule drug design. Herein, we report a transition-state analogue, a small, immucillin-derived inhibitor, as a new lead structure with a novel mode of action. The complex inhibitor synthesis was accomplished in 18 steps with an overall yield of 3 %. A co-crystal structure of the inhibitor bound to Z. mobilis TGT confirmed the predicted conformation of the immucillin derivative in the enzyme active site.
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Affiliation(s)
- Christoph Hohn
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Adrian Härtsch
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Frederik Rainer Ehrmann
- Institut für Pharmazeutische Chemie, Philipps Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany
| | - Toni Pfaffeneder
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Nils Trapp
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - Oliver Dumele
- Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, HCI, 8093, Zurich, Switzerland
| | - 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.
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15
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Manna S, Harman A. Horizontal gene transfer of a Chlamydial tRNA-guanine transglycosylase gene to eukaryotic microbes. Mol Phylogenet Evol 2015; 94:392-6. [PMID: 26435002 DOI: 10.1016/j.ympev.2015.09.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 09/14/2015] [Accepted: 09/26/2015] [Indexed: 10/23/2022]
Abstract
tRNA-guanine transglycosylases are found in all domains of life and mediate the base exchange of guanine with queuine in the anticodon loop of tRNAs. They can also regulate virulence in bacteria such as Shigella flexneri, which has prompted the development of drugs that inhibit the function of these enzymes. Here we report a group of tRNA-guanine transglycosylases in eukaryotic microbes (algae and protozoa) which are more similar to their bacterial counterparts than previously characterized eukaryotic tRNA-guanine transglycosylases. We provide evidence demonstrating that the genes encoding these enzymes were acquired by these eukaryotic lineages via horizontal gene transfer from the Chlamydiae group of bacteria. Given that the S. flexneri tRNA-guanine transglycosylase can be targeted by drugs, we propose that the bacterial-like tRNA-guanine transglycosylases could potentially be targeted in a similar fashion in pathogenic amoebae that possess these enzymes such as Acanthamoeba castellanii. This work also presents ancient prokaryote-to-eukaryote horizontal gene transfer events as an untapped resource of potential drug target identification in pathogenic eukaryotes.
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Affiliation(s)
- Sam Manna
- Department of Physiology, Anatomy & Microbiology, La Trobe University, Melbourne, Victoria, Australia.
| | - Ashley Harman
- Department of Physiology, Anatomy & Microbiology, La Trobe University, Melbourne, Victoria, Australia
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16
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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]
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17
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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: 419] [Impact Index Per Article: 46.6] [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.
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Affiliation(s)
- Elke Persch
- Laboratorium für Organische Chemie, Departement Chemie und Angewandte Biowissenschaften, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich (Switzerland)
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18
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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]
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19
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Grüner S, Neeb M, Barandun LJ, Sielaff F, Hohn C, Kojima S, Steinmetzer T, Diederich F, Klebe G. Impact of protein and ligand impurities on ITC-derived protein–ligand thermodynamics. Biochim Biophys Acta Gen Subj 2014; 1840:2843-50. [DOI: 10.1016/j.bbagen.2014.04.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/23/2014] [Accepted: 04/25/2014] [Indexed: 11/28/2022]
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20
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Jakobi S, Nguyen TXP, Debaene F, Metz A, Sanglier-Cianférani S, Reuter K, Klebe G. Hot-spot analysis to dissect the functional protein-protein interface of a tRNA-modifying enzyme. Proteins 2014; 82:2713-32. [DOI: 10.1002/prot.24637] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/24/2014] [Accepted: 06/18/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Stephan Jakobi
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg; Marbacher Weg 6 D-35032 Marburg Germany
| | - Tran Xuan Phong Nguyen
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg; Marbacher Weg 6 D-35032 Marburg Germany
| | - François Debaene
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), IPHC-DSA, Université de Strasbourg; CNRS UMR7178; 25 rue Becquerel 67087 Strasbourg France
| | - Alexander Metz
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg; Marbacher Weg 6 D-35032 Marburg Germany
| | - Sarah Sanglier-Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), IPHC-DSA, Université de Strasbourg; CNRS UMR7178; 25 rue Becquerel 67087 Strasbourg France
| | - Klaus Reuter
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg; Marbacher Weg 6 D-35032 Marburg Germany
| | - Gerhard Klebe
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg; Marbacher Weg 6 D-35032 Marburg Germany
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21
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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
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22
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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.
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Affiliation(s)
- Manuel Neeb
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg , Marbacher Weg 6, 35032 Marburg, Germany
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23
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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]
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24
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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.
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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
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25
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Xu J, Li J, Wei Z, Zhang Q, Shi D. Direct amination of azoles using CuCl2 complexes of amines under mild conditions. RSC Adv 2013. [DOI: 10.1039/c3ra41496e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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26
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Carell T, Brandmayr C, Hienzsch A, Müller M, Pearson D, Reiter V, Thoma I, Thumbs P, Wagner M. Struktur und Funktion nicht-kanonischer Nukleobasen. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201193] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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27
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Carell T, Brandmayr C, Hienzsch A, Müller M, Pearson D, Reiter V, Thoma I, Thumbs P, Wagner M. Structure and function of noncanonical nucleobases. Angew Chem Int Ed Engl 2012; 51:7110-31. [PMID: 22744788 DOI: 10.1002/anie.201201193] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/07/2012] [Indexed: 12/19/2022]
Abstract
DNA and RNA contain, next to the four canonical nucleobases, a number of modified nucleosides that extend their chemical information content. RNA is particularly rich in modifications, which is obviously an adaptation to their highly complex and variable functions. In fact, the modified nucleosides and their chemical structures establish a second layer of information which is of central importance to the function of the RNA molecules. Also the chemical diversity of DNA is greater than originally thought. Next to the four canonical bases, the DNA of higher organisms contains a total of four epigenetic bases: m(5) dC, hm(5) dC, f(5) dC und ca(5) dC. While all cells of an organism contain the same genetic material, their vastly different function and properties inside complex higher organisms require the controlled silencing and activation of cell-type specific genes. The regulation of the underlying silencing and activation process requires an additional layer of epigenetic information, which is clearly linked to increased chemical diversity. This diversity is provided by the modified non-canonical nucleosides in both DNA and RNA.
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Affiliation(s)
- Thomas Carell
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany.
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28
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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.
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Affiliation(s)
- Luzi Jakob Barandun
- Laboratorium für Organische Chemie, ETH Zürich, Hönggerberg, HCI, 8093 Zurich, Switzerland
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29
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Iminoheterocycle as a druggable motif: BACE1 inhibitors and beyond. Trends Pharmacol Sci 2012; 33:233-40. [DOI: 10.1016/j.tips.2012.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/01/2012] [Accepted: 02/21/2012] [Indexed: 11/20/2022]
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30
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Lecoutey C, Fossey C, Rault S, Fabis F. Efficient Room-Temperature One-Pot Synthesis of 2-Amino-3-alkyl(3-aryl)quinazolin-4(3H)-ones. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100200] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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31
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Affiliation(s)
- Caterina Bissantz
- Discovery Chemistry, F. Hoffmann-La Roche AG, CH-4070 Basel, Switzerland
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32
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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.
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Affiliation(s)
- Tina Ritschel
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany
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33
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Liu Y, Wu X, He C, Li Z, Duan C. Metal–organic polyhedra for selective sensing of ribonucleosides through the cooperation of hydrogen-bonding interactions. Dalton Trans 2010; 39:7727-32. [DOI: 10.1039/c0dt00002g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Abstract
tRNAs possess a high content of modified nucleosides, which display an incredible structural variety. These modified nucleosides are conserved in their sequence and have important roles in tRNA functions. Most often, hypermodified nucleosides are found in the wobble position of tRNAs, which play a direct role in maintaining translational efficiency and fidelity, codon recognition, etc. One of such hypermodified base is queuine, which is a base analogue of guanine, found in the first anticodon position of specific tRNAs (tyrosine, histidine, aspartate and asparagine tRNAs). These tRNAs of the ‘Q-family’ originally contain guanine in the first position of anticodon, which is post-transcriptionally modified with queuine by an irreversible insertion during maturation. Queuine is ubiquitously present throughout the living system from prokaryotes to eukaryotes, including plants. Prokaryotes can synthesize queuine de novo by a complex biosynthetic pathway, whereas eukaryotes are unable to synthesize either the precursor or queuine. They utilize salvage system and acquire queuine as a nutrient factor from their diet or from intestinal microflora. The tRNAs of the Q-family are completely modified in terminally differentiated somatic cells. However, hypomodification of Q-tRNA (queuosine-modified tRNA) is closely associated with cell proliferation and malignancy. The precise mechanisms of queuine- and Q-tRNA-mediated action are still a mystery. Direct or indirect evidence suggests that queuine or Q-tRNA participates in many cellular functions, such as inhibition of cell proliferation, control of aerobic and anaerobic metabolism, bacterial virulence, etc. The role of Q-tRNA modification in cellular machinery and the signalling pathways involved therein is the focus of this review.
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35
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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]
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36
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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]
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37
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Ritschel T, Hoertner S, Heine A, Diederich F, Klebe G. Crystal structure analysis and in silico pKa calculations suggest strong pKa shifts of ligands as driving force for high-affinity binding to TGT. Chembiochem 2009; 10:716-27. [PMID: 19199329 DOI: 10.1002/cbic.200800782] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel ligand series is presented to inhibit tRNA-guanine transglycosylase (TGT), a protein with a significant role in the pathogenicity mechanism of Shigella flexneri, the causative agent of Shigellosis. The enzyme exchanges guanine in the wobble position of tRNA(Asn,Asp,His,Tyr) against a modified base. To prevent the base-exchange reaction, several series of inhibitors have already been designed, synthesized, and tested. One aim of previous studies was to address a hydrophobic pocket with different side chains attached to the parent skeletons. Disappointingly, no significant increase in binding affinity could be observed that could be explained by the disruption of a conserved water cluster. The ligand series examined in this study are based on the known scaffold lin-benzoguanine. Different side chains were introduced leading to 2-amino-lin-benzoguanines, which address a different pocket of the protein and avoid disruption of the water cluster. With the introduction of an amino group in the 2-position, a dramatic increase in binding affinity can be experienced. To explain this significant gain in binding affinity, Poisson-Boltzmann calculations were performed to explore pK(a) changes of ligand functional groups upon protein binding, they can differ significantly on going from aqueous solution to protein environment. For all complexes, a permanent protonation of the newly designed ligands is suggested, leading to a charge-assisted hydrogen bond in the protein-ligand complex. This increased strength in hydrogen bonding takes beneficial effect on binding affinity of the ligands, resulting in low-nanomolar binders. Crystal structures and docking emphasize the importance of the newly created charge-assisted hydrogen bond. A detailed analysis of the crystal structures in complex with substituted 2-amino-lin-benzoguanines indicate pronounced disorder of the attached side chains addressing the ribose 33 binding pocket. Docking suggests multiple orientations of these side chains. Obviously, an entropic advantage of the residual mobility experienced by these ligands in the bound state is beneficial and reveals an overall improved protein binding.
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Affiliation(s)
- Tina Ritschel
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, Marburg, Germany
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A fluorine scan of non-peptidic inhibitors of neprilysin: Fluorophobic and fluorophilic regions in an enzyme active site. J Fluor Chem 2008. [DOI: 10.1016/j.jfluchem.2008.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Zürcher M, Diederich F. Structure-Based Drug Design: Exploring the Proper Filling of Apolar Pockets at Enzyme Active Sites. J Org Chem 2008; 73:4345-61. [DOI: 10.1021/jo800527n] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martina Zürcher
- Department of Chemistry and Applied Biosciences, Laboratorium für Organische Chemie, ETH Zürich, HCI G 313, 8093 Zürich, Switzerland
| | - François Diederich
- Department of Chemistry and Applied Biosciences, Laboratorium für Organische Chemie, ETH Zürich, HCI G 313, 8093 Zürich, Switzerland
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