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Anthony Maxwell - One of the best experts on this subject based on the ideXlab platform.
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the pentapeptide repeat protein mfpa interacts with mycobacterial dna Gyrase as a dna t segment mimic
Proceedings of the National Academy of Sciences of the United States of America, 2021Co-Authors: Lipeng Feng, Lesley A Mitchenall, Julia E A Mundy, Clare E M Stevenson, David M Lawson, Anthony MaxwellAbstract:DNA Gyrase, a type II topoisomerase, introduces negative supercoils into DNA using ATP hydrolysis. The highly effective Gyrase-targeted drugs, fluoroquinolones (FQs), interrupt Gyrase by stabilizing a DNA-cleavage complex, a transient intermediate in the supercoiling cycle, leading to double-stranded DNA breaks. MfpA, a pentapeptide-repeat protein in mycobacteria, protects Gyrase from FQs, but its molecular mechanism remains unknown. Here, we show that Mycobacterium smegmatis MfpA (MsMfpA) inhibits negative supercoiling by M. smegmatis Gyrase (MsGyrase) in the absence of FQs, while in their presence, MsMfpA decreases FQ-induced DNA cleavage, protecting the enzyme from these drugs. MsMfpA stimulates the ATPase activity of MsGyrase by directly interacting with the ATPase domain (MsGyrB47), which was confirmed through X-ray crystallography of the MsMfpA-MsGyrB47 complex, and mutational analysis, demonstrating that MsMfpA mimics a T (transported) DNA segment. These data reveal the molecular mechanism whereby MfpA modulates the activity of Gyrase and may provide a general molecular basis for the action of other pentapeptide-repeat proteins.
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dna Gyrase is the target for the quinolone drug ciprofloxacin in arabidopsis thaliana
Journal of Biological Chemistry, 2016Co-Authors: Katherine M Evansroberts, Lesley A Mitchenall, Melisa K. Wall, Julie Leroux, Joshua S Mylne, Anthony MaxwellAbstract:The Arabidopsis thaliana genome contains four genes that were originally annotated as potentially encoding DNA Gyrase: ATGYRA, ATGYRB1, ATGYRB2, and ATGYRB3. Although we subsequently showed that ATGYRB3 does not encode a Gyrase subunit, the other three genes potentially encode subunits of a plant Gyrase. We also showed evidence for the existence of supercoiling activity in A. thaliana and that the plant is sensitive to quinolone and aminocoumarin antibiotics, compounds that target DNA Gyrase in bacteria. However, it was not possible at that time to show whether the A. thaliana genes encoded an active Gyrase enzyme, nor whether that enzyme is indeed the target for the quinolone and aminocoumarin antibiotics. Here we show that an A. thaliana mutant resistant to the quinolone drug ciprofloxacin has a point mutation in ATGYRA. Moreover we show that, as in bacteria, the quinolone-sensitive (wild-type) allele is dominant to the resistant gene. Further we have heterologously expressed ATGYRA and ATGYRB2 in a baculovirus expression system and shown supercoiling activity of the partially purified enzyme. Expression/purification of the quinolone-resistant A. thaliana Gyrase yields active enzyme that is resistant to ciprofloxacin. Taken together these experiments now show unequivocally that A. thaliana encodes an organelle-targeted DNA Gyrase that is the target of the quinolone drug ciprofloxacin; this has important consequences for plant physiology and the development of herbicides.
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the naphthoquinone diospyrin is an inhibitor of dna Gyrase with a novel mechanism of action
Journal of Biological Chemistry, 2013Co-Authors: Shantanu Karkare, Namrita Lall, La Mitchenall, Sj Greive, Terence T H Chung, Frederic Collin, Adam R Mckay, Jacobus Johannes Marion Meyer, Anthony MaxwellAbstract:Abstract Tuberculosis and other bacterial diseases represent a significant threat to human health. The DNA topoisomerases are excellent targets for chemotherapy, and DNA Gyrase in particular is a well-validated target for antibacterial agents. Naphthoquinones (e.g. diospyrin and 7-methyljuglone) have been shown to have therapeutic potential, particularly against Mycobacterium tuberculosis. We have found that these compounds are inhibitors of the supercoiling reaction catalyzed by M. tuberculosis Gyrase and other Gyrases. Our evidence strongly suggests that the compounds bind to the N-terminal domain of GyrB, which contains the ATPase active site, but are not competitive inhibitors of the ATPase reaction. We propose that naphthoquinones bind to GyrB at a novel site close to the ATPase site. This novel mode of action could be exploited to develop new antibacterial agents.
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the naphthoquinone diospyrin is an inhibitor of dna Gyrase with a novel mechanism of action
Journal of Biological Chemistry, 2013Co-Authors: Shantanu Karkare, Lesley A Mitchenall, Namrita Lall, Sj Greive, Terence T H Chung, Frederic Collin, Adam R Mckay, Jacobus Johannes Marion Meyer, Anthony MaxwellAbstract:Tuberculosis and other bacterial diseases represent a significant threat to human health. The DNA topoisomerases are excellent targets for chemotherapy, and DNA Gyrase in particular is a well-validated target for antibacterial agents. Naphthoquinones (e.g. diospyrin and 7-methyljuglone) have been shown to have therapeutic potential, particularly against Mycobacterium tuberculosis. We have found that these compounds are inhibitors of the supercoiling reaction catalyzed by M. tuberculosis Gyrase and other Gyrases. Our evidence strongly suggests that the compounds bind to the N-terminal domain of GyrB, which contains the ATPase active site, but are not competitive inhibitors of the ATPase reaction. We propose that naphthoquinones bind to GyrB at a novel site close to the ATPase site. This novel mode of action could be exploited to develop new antibacterial agents. Background: New antibacterial compounds are urgently needed; DNA Gyrase is a well-validated target. Results: Diospyrin and other naphthoquinones inhibit DNA Gyrase by binding to a novel site in the B subunit. Conclusion: Naphthoquinones are inhibitors of Gyrase with a novel mechanism of action. Significance: Naphthoquinones have potential as antibacterial compounds against TB.
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Inhibition of DNA Gyrase and DNA topoisomerase IV of Staphylococcus aureus and Escherichia coli by aminocoumarin antibiotics
The Journal of antimicrobial chemotherapy, 2011Co-Authors: Silke Alt, Lesley A Mitchenall, Anthony Maxwell, Lutz HeideAbstract:Objectives Aminocoumarin antibiotics are potent inhibitors of bacterial DNA Gyrase. We investigated the inhibitory and antibacterial activity of naturally occurring aminocoumarin antibiotics and six structural analogues (novclobiocins) against DNA Gyrase and DNA topoisomerase IV from Escherichia coli and Staphylococcus aureus as well as the effect of potassium and sodium glutamate on the activity of these enzymes. Methods The inhibitory concentrations of the aminocoumarins were determined in Gyrase supercoiling assays and topoisomerase IV decatenation assays. Both subunits of S. aureus topoisomerase IV were purified as His-Tag proteins in E. coli. The MIC was tested in vivo for the control organisms E. coli ATCC 25922 and S. aureus ATCC 29213. Results DNA Gyrase is the primary target in vitro of all investigated aminocoumarins. With the exception of simocyclinone D8, all other aminocoumarins inhibited S. aureus Gyrase on average 6-fold more effectively than E. coli Gyrase. Potassium glutamate is essential for the activity of S. aureus Gyrase and increases the sensitivity of E. coli Gyrase to aminocoumarins ≥ 10-fold. The antibacterial activity of the tested compounds mirrored their relative activities against topoisomerases. Conclusions The study provides insights about the substituents that are important for the inhibitory activity of aminocoumarins against the target enzymes, which will facilitate the rational design of improved antibiotics.
Danijel Kikelj - One of the best experts on this subject based on the ideXlab platform.
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Design, synthesis and biological evaluation of 4,5-dibromo-N-(thiazol-2-yl)-1H-pyrrole-2-carboxamide derivatives as novel DNA Gyrase inhibitors.
Bioorganic & Medicinal Chemistry, 2017Co-Authors: Tihomir Tomašič, Michaela Barančoková, Janez Ilaš, Päivi Tammela, Nace Zidar, Matic Mirt, Danijel KikeljAbstract:Development of novel DNA Gyrase B inhibitors is an important field of antibacterial drug discovery whose aim is to introduce a more effective representative of this mechanistic class into the clinic. In the present study, two new series of Escherichia coli DNA Gyrase inhibitors bearing the 4,5-dibromopyrrolamide moiety have been designed and synthesized. 4,5,6,7-Tetrahydrobenzo[1,2-d]thiazole-2,6-diamine derivatives inhibited E. coli DNA Gyrase in the submicromolar to low micromolar range (IC50 values between 0.891 and 10.4 microM). Their ''ring-opened'' analogues, based on the 2-(2-aminothiazol-4-yl)acetic acid scaffold, displayed weaker DNA Gyrase inhibition with IC50 values between 15.9 and 169 microM. Molecular docking experiments were conducted to study the binding modes of inhibitors.
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Discovery of Benzothiazole Scaffold-Based DNA Gyrase B Inhibitors
Journal of medicinal chemistry, 2016Co-Authors: Marina Gjorgjieva, Michaela Barančoková, Lucija Peterlin Mašič, Janez Ilaš, Päivi Tammela, Sotirios Katsamakas, Tihomir Tomašič, Danijel KikeljAbstract:Bacterial DNA Gyrase and topoisomerase IV control the topological state of DNA during replication and are validated targets for antibacterial drug discovery. Starting from our recently reported 4,5,6,7-tetrahydrobenzo[1,2-d]thiazole-based DNA Gyrase B inhibitors, we replaced their central core with benzothiazole-2,6-diamine scaffold and interchanged substituents in positions 2 and 6. This resulted in equipotent nanomolar inhibitors of DNA Gyrase from Escherichia coli displaying improved inhibition of Staphylococcus aureus DNA Gyrase and topoisomerase IV from both bacteria. Compound 27 was the most balanced inhibitor of DNA Gyrase and topoisomerase IV from both E. coli and S. aureus. The crystal structure of the 2-((2-(4,5-dibromo-1H-pyrrole-2-carboxamido)benzothiazol-6-yl)amino)-2-oxoacetic acid (24) in complex with E. coli DNA Gyrase B revealed the binding mode of the inhibitor in the ATP-binding pocket. Only some compounds possessed weak antibacterial activity against Gram-positive bacteria. These resul...
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Discovery of Benzothiazole Scaffold-Based DNA Gyrase B Inhibitors
2016Co-Authors: Marina Gjorgjieva, Tihomir Tomašič, Michaela Barančokova, Sotirios Katsamakas, Janez Ilaš, Päivi Tammela, Lucija Peterlin Mašič, Danijel KikeljAbstract:Bacterial DNA Gyrase and topoisomerase IV control the topological state of DNA during replication and are validated targets for antibacterial drug discovery. Starting from our recently reported 4,5,6,7-tetrahydrobenzo[1,2-d]thiazole-based DNA Gyrase B inhibitors, we replaced their central core with benzothiazole-2,6-diamine scaffold and interchanged substituents in positions 2 and 6. This resulted in equipotent nanomolar inhibitors of DNA Gyrase from Escherichia coli displaying improved inhibition of Staphylococcus aureus DNA Gyrase and topoisomerase IV from both bacteria. Compound 27 was the most balanced inhibitor of DNA Gyrase and topoisomerase IV from both E. coli and S. aureus. The crystal structure of the 2-((2-(4,5-dibromo-1H-pyrrole-2-carboxamido)benzothiazol-6-yl)amino)-2-oxoacetic acid (24) in complex with E. coli DNA Gyrase B revealed the binding mode of the inhibitor in the ATP-binding pocket. Only some compounds possessed weak antibacterial activity against Gram-positive bacteria. These results provide a basis for structure-based optimization toward dual DNA Gyrase and topoisomerase IV inhibitors with antibacterial activity
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n phenyl 4 5 dibromopyrrolamides and n phenylindolamides as atp competitive dna Gyrase b inhibitors design synthesis and evaluation
Journal of Medicinal Chemistry, 2015Co-Authors: Nace Zidar, Lucija Peterlin Mašič, Janez Ilaš, Päivi Tammela, Tihomir Tomašič, Helena Macut, Matjaž Brvar, Sofia Montalvao, Tom Solmajer, Danijel KikeljAbstract:Bacterial DNA Gyrase is a well-known and validated target in the design of antibacterial drugs. However, inhibitors of its ATP binding subunit, DNA Gyrase B (GyrB), have so far not reached clinical use. In the present study, three different series of N-phenyl-4,5-dibromopyrrolamides and N-phenylindolamides were designed and prepared as potential DNA Gyrase B inhibitors. The IC50 values of compounds on DNA Gyrase from Escherichia coli were in the low micromolar range, with the best compound, (4-(4,5-dibromo-1H-pyrrole-2-carboxamido)benzoyl)glycine (18a), displaying an IC50 of 450 nM. For this compound, a high-resolution crystal structure in complex with E. coli DNA Gyrase B was obtained, revealing details of its binding mode within the active site. The binding affinities of three compounds with GyrB were additionally evaluated by surface plasmon resonance, and the results were in good agreement with the determined enzymatic activities. For the most promising compounds, the inhibitory activities against DNA...
Emmanuelle Cambau - One of the best experts on this subject based on the ideXlab platform.
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target specificity of the new fluoroquinolone besifloxacin in streptococcus pneumoniae staphylococcus aureus and escherichia coli
Journal of Antimicrobial Chemotherapy, 2009Co-Authors: Emmanuelle Cambau, Alexandra Aubry, Stephanie Matrat, X S Pan, Romain Roth Dit Bettoni, Celine Corbel, C Lascols, Jeanyves Driot, Mark L FisherAbstract:Objectives Besifloxacin is a new fluoroquinolone in development for ocular use. We investigated its mode of action and resistance in two major ocular pathogens, Streptococcus pneumoniae and Staphylococcus aureus, and in the reference species Escherichia coli. Methods Primary and secondary targets of besifloxacin were evaluated by: (i) mutant selection experiments; (ii) MIC testing of defined topoisomerase mutants; and (iii) inhibition and cleavable complex assays with purified S. pneumoniae and E. coli DNA Gyrase and topoisomerase IV enzymes. Results Enzyme assays showed similar besifloxacin activity against S. pneumoniae Gyrase and topoisomerase IV, with IC(50) and CC(25) of 2.5 and 1 microM, respectively. In contrast to ciprofloxacin and moxifloxacin, besifloxacin was equally potent against both S. pneumoniae and E. coli Gyrases. DNA Gyrase was the primary target in all three species, with substitutions observed at positions 81, 83 and 87 in GyrA and 426 and 466 in GyrB (E. coli numbering). Topoisomerase IV was the secondary target. Notably, resistant mutants were not recovered at 4-fold besifloxacin MICs for S. aureus and S. pneumoniae, and S. aureus topoisomerase mutants were only obtained after serial passage in liquid medium. Besifloxacin MICs were similarly affected by parC or gyrA mutations in S. aureus and S. pneumoniae and remained below 1 mg/L in gyrA-parC double mutants. Conclusions Although mutant selection experiments indicated that Gyrase is a primary target, further biochemical and genetic studies showed that besifloxacin has potent, relatively balanced activity against both essential DNA Gyrase and topoisomerase IV targets in S. aureus and S. pneumoniae.
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the pentapeptide repeat proteins mfpamt and qnrb4 exhibit opposite effects on dna Gyrase catalytic reactions and on the ternary Gyrase dna quinolone complex
Journal of Bacteriology, 2009Co-Authors: Alexandra Aubry, Vincent Jarlier, Stephanie Matrat, C Lascols, Audrey Merens, C J Soussy, J D Cavallo, Emmanuelle CambauAbstract:MfpAMt and QnrB4 are two newly characterized pentapeptide repeat proteins (PRPs) that interact with DNA Gyrase. The mfpAMt gene is chromosome borne in Mycobacterium tuberculosis, while qnrB4 is plasmid borne in enterobacteria. We expressed and purified the two PRPs and compared their effects on DNA Gyrase, taking into account host specificity, i.e., the effect of MfpAMt on M. tuberculosis Gyrase and the effect of QnrB4 on Escherichia coli Gyrase. Whereas QnrB4 inhibited E. coli Gyrase activity only at concentrations higher than 30 μM, MfpAMt inhibited all catalytic reactions of the M. tuberculosis Gyrase described for this enzyme (supercoiling, cleavage, relaxation, and decatenation) with a 50% inhibitory concentration of 2 μM. We showed that the D87 residue in GyrA has a major role in the MfpAMt-Gyrase interaction, as D87H and D87G substitutions abolished MfpAMt inhibition of M. tuberculosis Gyrase catalytic reactions, while A83S modification did not. Since MfpAMt and QnrB4 have been involved in resistance to fluoroquinolones, we measured the inhibition of the quinolone effect in the presence of each PRP. QnrB4 reversed quinolone inhibition of E. coli Gyrase at 0.1 μM as described for other Qnr proteins, but MfpAMt did not modify M. tuberculosis Gyrase inhibition by fluoroquinolones. Crossover experiments showed that MfpAMt also inhibited E. coli Gyrase function, while QnrB4 did not reverse quinolone inhibition of M. tuberculosis Gyrase. In conclusion, our in vitro experiments showed that MfpAMt and QnrB4 exhibit opposite effects on DNA Gyrase and that these effects are protein and species specific.
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Target specificity of the new fluoroquinolone besifloxacin in Streptococcus pneumoniae, Staphylococcus aureus and Escherichia
2009Co-Authors: Emmanuelle Cambau, Stephanie Matrat, X S Pan, C Lascols, Jeanyves Driot, Romain Roth, Dit Bettoni, Ra Aubry, Mark L FisherAbstract:Objectives: Besifloxacin is a new fluoroquinolone in development for ocular use. We investigated its mode of action and resistance in two major ocular pathogens, Streptococcus pneumoniae and Staphylococcus aureus, and in the reference species Escherichia coli. Methods: Primary and secondary targets of besifloxacin were evaluated by: (i) mutant selection experi-ments; (ii) MIC testing of defined topoisomerase mutants; and (iii) inhibition and cleavable complex assays with purified S. pneumoniae and E. coli DNA Gyrase and topoisomerase IV enzymes. Results: Enzyme assays showed similar besifloxacin activity against S. pneumoniae Gyrase and topoi-somerase IV, with IC50 and CC25 of 2.5 and 1 mM, respectively. In contrast to ciprofloxacin and moxi-floxacin, besifloxacin was equally potent against both S. pneumoniae and E. coli Gyrases. DNA Gyrase was the primary target in all three species, with substitutions observed at positions 81, 83 and 87 in GyrA and 426 and 466 in GyrB (E. coli numbering). Topoisomerase IV was the secondary target. Notably, resistant mutants were not recovered at 4-fold besifloxacin MICs for S. aureus and S. pneumoniae, and S. aureus topoisomerase mutants were only obtained after serial passage in liquid medium. Besifloxacin MICs were similarly affected by parC or gyrA mutations in S. aureus and S. pneumoniae and remained below 1 mg/L in gyrA–parC double mutants
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First functional characterization of a singly expressed bacterial type II topoisomerase: the enzyme from Mycobacterium tuberculosis.
Biochemical and biophysical research communications, 2006Co-Authors: Alexandra Aubry, L. Mark Fisher, Vincent Jarlier, Emmanuelle CambauAbstract:Genome deciphering revealed that Mycobacterium tuberculosis encodes a single type II topoisomerase contrary to common bacteria harboring two type II topoisomerases (DNA Gyrase and topoisomerase IV). Functions of the M. tuberculosis type II topoisomerase were explored after cloning and expressing the subunits encoding genes in Escherichia coli. M. tuberculosis type II topoisomerase supercoiled relaxed pBR322 with a specific activity close to that of DNA Gyrases of common bacteria whereas it exhibited DNA relaxation and formation of cleavable complexes with activities significantly higher than other DNA Gyrases. Intermolecular passage activity evaluated by the decatenation of kinetoplast DNA was 25-fold lower than that of the topoisomerase IV from Streptococcus pneumoniae, but was markedly higher than that of the E. coli Gyrase. Overall, the type II topoisomerase of M. tuberculosis exhibits classical polyvalent activities of DNA Gyrase for supercoiling but enhanced relaxation, cleavage, and decatenation activities.
Alexandra Aubry - One of the best experts on this subject based on the ideXlab platform.
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Overall Structures of Mycobacterium tuberculosis DNA Gyrase Reveal the Role of a Corynebacteriales GyrB-Specific Insert in ATPase Activity
Structure, 2019Co-Authors: Stéphanie Petrella, Alexandra Aubry, Estelle Capton, Bertrand Raynal, Clément Giffard, Aurélien Thureau, Françoise Bonneté, Pedro Alzari, Claudine MayerAbstract:Despite sharing common features, previous studies have shown that Gyrases from different species have been modified throughout evolution to modulate their properties. Here, we report two crystal structures of Mycobacterium tuberculosis DNA Gyrase, an apo and AMPPNP-bound form at 2.6-Å and 3.3-Å resolution, respectively. These structures provide high-resolution structural data on the quaternary organization and interdomain connections of a Gyrase (full-length GyrB-GyrA57)2 thus providing crucial inputs on this essential drug target. Together with small-angle X-ray scattering studies, they revealed an "extremely open" N-gate state, which persists even in the DNA-free Gyrase-AMPPNP complex and an unexpected connection between the ATPase and cleavage core domains mediated by two Corynebacteriales-specific motifs, respectively the C-loop and DEEE-loop. We show that the C-loop participates in the stabilization of this open conformation, explaining why this Gyrase has a lower ATPase activity. Our results image a conformational state which might be targeted for drug discovery.
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target specificity of the new fluoroquinolone besifloxacin in streptococcus pneumoniae staphylococcus aureus and escherichia coli
Journal of Antimicrobial Chemotherapy, 2009Co-Authors: Emmanuelle Cambau, Alexandra Aubry, Stephanie Matrat, X S Pan, Romain Roth Dit Bettoni, Celine Corbel, C Lascols, Jeanyves Driot, Mark L FisherAbstract:Objectives Besifloxacin is a new fluoroquinolone in development for ocular use. We investigated its mode of action and resistance in two major ocular pathogens, Streptococcus pneumoniae and Staphylococcus aureus, and in the reference species Escherichia coli. Methods Primary and secondary targets of besifloxacin were evaluated by: (i) mutant selection experiments; (ii) MIC testing of defined topoisomerase mutants; and (iii) inhibition and cleavable complex assays with purified S. pneumoniae and E. coli DNA Gyrase and topoisomerase IV enzymes. Results Enzyme assays showed similar besifloxacin activity against S. pneumoniae Gyrase and topoisomerase IV, with IC(50) and CC(25) of 2.5 and 1 microM, respectively. In contrast to ciprofloxacin and moxifloxacin, besifloxacin was equally potent against both S. pneumoniae and E. coli Gyrases. DNA Gyrase was the primary target in all three species, with substitutions observed at positions 81, 83 and 87 in GyrA and 426 and 466 in GyrB (E. coli numbering). Topoisomerase IV was the secondary target. Notably, resistant mutants were not recovered at 4-fold besifloxacin MICs for S. aureus and S. pneumoniae, and S. aureus topoisomerase mutants were only obtained after serial passage in liquid medium. Besifloxacin MICs were similarly affected by parC or gyrA mutations in S. aureus and S. pneumoniae and remained below 1 mg/L in gyrA-parC double mutants. Conclusions Although mutant selection experiments indicated that Gyrase is a primary target, further biochemical and genetic studies showed that besifloxacin has potent, relatively balanced activity against both essential DNA Gyrase and topoisomerase IV targets in S. aureus and S. pneumoniae.
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the pentapeptide repeat proteins mfpamt and qnrb4 exhibit opposite effects on dna Gyrase catalytic reactions and on the ternary Gyrase dna quinolone complex
Journal of Bacteriology, 2009Co-Authors: Alexandra Aubry, Vincent Jarlier, Stephanie Matrat, C Lascols, Audrey Merens, C J Soussy, J D Cavallo, Emmanuelle CambauAbstract:MfpAMt and QnrB4 are two newly characterized pentapeptide repeat proteins (PRPs) that interact with DNA Gyrase. The mfpAMt gene is chromosome borne in Mycobacterium tuberculosis, while qnrB4 is plasmid borne in enterobacteria. We expressed and purified the two PRPs and compared their effects on DNA Gyrase, taking into account host specificity, i.e., the effect of MfpAMt on M. tuberculosis Gyrase and the effect of QnrB4 on Escherichia coli Gyrase. Whereas QnrB4 inhibited E. coli Gyrase activity only at concentrations higher than 30 μM, MfpAMt inhibited all catalytic reactions of the M. tuberculosis Gyrase described for this enzyme (supercoiling, cleavage, relaxation, and decatenation) with a 50% inhibitory concentration of 2 μM. We showed that the D87 residue in GyrA has a major role in the MfpAMt-Gyrase interaction, as D87H and D87G substitutions abolished MfpAMt inhibition of M. tuberculosis Gyrase catalytic reactions, while A83S modification did not. Since MfpAMt and QnrB4 have been involved in resistance to fluoroquinolones, we measured the inhibition of the quinolone effect in the presence of each PRP. QnrB4 reversed quinolone inhibition of E. coli Gyrase at 0.1 μM as described for other Qnr proteins, but MfpAMt did not modify M. tuberculosis Gyrase inhibition by fluoroquinolones. Crossover experiments showed that MfpAMt also inhibited E. coli Gyrase function, while QnrB4 did not reverse quinolone inhibition of M. tuberculosis Gyrase. In conclusion, our in vitro experiments showed that MfpAMt and QnrB4 exhibit opposite effects on DNA Gyrase and that these effects are protein and species specific.
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First functional characterization of a singly expressed bacterial type II topoisomerase: the enzyme from Mycobacterium tuberculosis.
Biochemical and biophysical research communications, 2006Co-Authors: Alexandra Aubry, L. Mark Fisher, Vincent Jarlier, Emmanuelle CambauAbstract:Genome deciphering revealed that Mycobacterium tuberculosis encodes a single type II topoisomerase contrary to common bacteria harboring two type II topoisomerases (DNA Gyrase and topoisomerase IV). Functions of the M. tuberculosis type II topoisomerase were explored after cloning and expressing the subunits encoding genes in Escherichia coli. M. tuberculosis type II topoisomerase supercoiled relaxed pBR322 with a specific activity close to that of DNA Gyrases of common bacteria whereas it exhibited DNA relaxation and formation of cleavable complexes with activities significantly higher than other DNA Gyrases. Intermolecular passage activity evaluated by the decatenation of kinetoplast DNA was 25-fold lower than that of the topoisomerase IV from Streptococcus pneumoniae, but was markedly higher than that of the E. coli Gyrase. Overall, the type II topoisomerase of M. tuberculosis exhibits classical polyvalent activities of DNA Gyrase for supercoiling but enhanced relaxation, cleavage, and decatenation activities.
Hailiang Zhu - One of the best experts on this subject based on the ideXlab platform.
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synthesis structure and antibacterial activity of potent dna Gyrase inhibitors n benzoyl 3 4 bromophenyl 1h pyrazole 5 carbohydrazide derivatives
PLOS ONE, 2013Co-Authors: Juan Sun, Hailiang Zhu, Yong Yin, Rongju YuanAbstract:A total of 19 novel (3a–3s) N′-benzoyl-3-(4-bromophenyl)-1H-pyrazole-5-carbohydrazide analogs were designed, synthesized, and evaluated for biological activities as potential DNA Gyrase inhibitors. The results showed that compound 3k can strongly inhibit Staphylococcus aureus DNA Gyrase and Bacillus subtilis DNA Gyrase (with IC50 of 0.15 µg/mL and 0.25 µg/mL, respectively). Structure-activity relationships were also discussed base on the biological and docking simulation results.
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synthesis structure and antibacterial activity of new 2 1 2 substituted phenyl 5 methyloxazol 4 yl 3 2 substitued phenyl 4 5 dihydro 1h pyrazol 5 yl 7 substitued 1 2 3 4 tetrahydroisoquinoline derivatives
Bioorganic & Medicinal Chemistry, 2009Co-Authors: Xinhua Liu, Jing Zhu, Anna Zhou, Baoan Song, Hailiang Zhu, Linshan Bai, Pinaki S Bhadury, Chunxiu PanAbstract:Abstract A series of new 2-(1-(2-(substituted-phenyl)-5-methyloxazol-4-yl)-3-(2-substitued-phenyl)-4,5-dihydro-1 H -pyrazol-5-yl)-7-substitued - 1,2,3,4-tetrahydroisoquinoline derivatives were synthesized. The results showed that compounds 9q and 10q can strongly inhibit Staphylococcus aureus DNA Gyrase and Bacillus subtilis DNA Gyrase (with IC 50s of 0.125 and 0.25 μg/mL against S. aureus DNA Gyrase , 0.25 and 0.125 μg/mL against B. subtilis DNA Gyrase). On the basis of the biological results, structure–activity relationships were also discussed.