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ACS Infectious Diseases Apr 2024Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone... (Review)
Review
Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone antibacterials. These drugs act by stabilizing gyrase/topoisomerase IV-generated DNA strand breaks and by robbing the cell of the catalytic activities of these essential enzymes. Since their clinical approval in the mid-1980s, fluoroquinolones have been used to treat a broad spectrum of infectious diseases and are listed among the five "highest priority" critically important antimicrobial classes by the World Health Organization. Unfortunately, the widespread use of fluoroquinolones has been accompanied by a rise in target-mediated resistance caused by specific mutations in gyrase and topoisomerase IV, which has curtailed the medical efficacy of this drug class. As a result, efforts are underway to identify novel antibacterials that target the bacterial type II topoisomerases. Several new classes of gyrase/topoisomerase IV-targeted antibacterials have emerged, including novel bacterial topoisomerase inhibitors, gyrase inhibitors, triazaacenaphthylenes, spiropyrimidinetriones, and thiophenes. Phase III clinical trials that utilized two members of these classes, gepotidacin (triazaacenaphthylene) and zoliflodacin (spiropyrimidinetrione), have been completed with positive outcomes, underscoring the potential of these compounds to become the first new classes of antibacterials introduced into the clinic in decades. Because gyrase and topoisomerase IV are validated targets for established and emerging antibacterials, this review will describe the catalytic mechanism and cellular activities of the bacterial type II topoisomerases, their interactions with fluoroquinolones, the mechanism of target-mediated fluoroquinolone resistance, and the actions of novel antibacterials against wild-type and fluoroquinolone-resistant gyrase and topoisomerase IV.
Topics: DNA Topoisomerase IV; Fluoroquinolones; DNA Gyrase; Topoisomerase II Inhibitors; Anti-Bacterial Agents; DNA; Mycobacterium tuberculosis
PubMed: 38564341
DOI: 10.1021/acsinfecdis.4c00128 -
Nucleic Acids Research May 2018Imidazopyrazinones (IPYs) are a new class of compounds that target bacterial topoisomerases as a basis for their antibacterial activity. We have characterized the...
Imidazopyrazinones (IPYs) are a new class of compounds that target bacterial topoisomerases as a basis for their antibacterial activity. We have characterized the mechanism of these compounds through structural/mechanistic studies showing they bind and stabilize a cleavage complex between DNA gyrase and DNA ('poisoning') in an analogous fashion to fluoroquinolones, but without the requirement for the water-metal-ion bridge. Biochemical experiments and structural studies of cleavage complexes of IPYs compared with an uncleaved gyrase-DNA complex, reveal conformational transitions coupled to DNA cleavage at the DNA gate. These involve movement at the GyrA interface and tilting of the TOPRIM domains toward the scissile phosphate coupled to capture of the catalytic metal ion. Our experiments show that these structural transitions are involved generally in poisoning of gyrase by therapeutic compounds and resemble those undergone by the enzyme during its adenosine triphosphate-coupled strand-passage cycle. In addition to resistance mutations affecting residues that directly interact with the compounds, we characterized a mutant (D82N) that inhibits formation of the cleavage complex by the unpoisoned enzyme. The D82N mutant appears to act by stabilizing the binary conformation of DNA gyrase with uncleaved DNA without direct interaction with the compounds. This provides general insight into the resistance mechanisms to antibiotics targeting bacterial type II topoisomerases.
Topics: Adenosine Triphosphate; Anti-Bacterial Agents; Ciprofloxacin; DNA; DNA Cleavage; DNA Gyrase; Drug Resistance, Bacterial; Fluoroquinolones; Magnesium; Models, Molecular; Mutation; Pyrazines; Topoisomerase II Inhibitors
PubMed: 29538767
DOI: 10.1093/nar/gky181 -
Antimicrobial Agents and Chemotherapy Oct 2023Antimicrobial resistance has made a sizeable impact on public health and continues to threaten the effectiveness of antibacterial therapies. Novel bacterial...
Antimicrobial resistance has made a sizeable impact on public health and continues to threaten the effectiveness of antibacterial therapies. Novel bacterial topoisomerase inhibitors (NBTIs) are a promising class of antibacterial agents with a unique binding mode and distinct pharmacology that enables them to evade existing resistance mechanisms. The clinical development of NBTIs has been plagued by several issues, including cardiovascular safety. Herein, we report a sub-series of tricyclic NBTIs bearing an amide linkage that displays promising antibacterial activity, potent dual-target inhibition of DNA gyrase and topoisomerase IV (TopoIV), as well as improved cardiovascular safety and metabolic profiles. These amide NBTIs induced both single- and double-strand breaks in pBR322 DNA mediated by DNA gyrase, in contrast to prototypical NBTIs that cause only single-strand breaks. Unexpectedly, amides and targeted human topoisomerase IIα (TOP2α) causing both single- and double-strand breaks in pBR322 DNA, and induced DNA strand breaks in intact human leukemia K562 cells. In addition, anticancer drug-resistant K/VP.5 cells containing decreased levels of TOP2α were cross-resistant to amides and . Together, these results demonstrate broad spectrum antibacterial properties of selected tricyclic NBTIs, desirable safety profiles, an unusual ability to induce DNA double-stranded breaks, and activity against human TOP2α. Future work will be directed toward optimization and development of tricyclic NBTIs with potent and selective activity against bacteria. Finally, the current results may provide an additional avenue for development of selective anticancer agents.
Topics: Humans; Topoisomerase Inhibitors; DNA Gyrase; DNA Topoisomerase IV; Anti-Bacterial Agents; Staphylococcus aureus; DNA; Amides; Topoisomerase II Inhibitors; Microbial Sensitivity Tests
PubMed: 37724886
DOI: 10.1128/aac.00482-23 -
Antimicrobial Agents and Chemotherapy May 2021The worldwide distribution of genes found on plasmids and their presence on the chromosomes of aquatic bacteria, such as , one of the suspected sources, suggests an...
The worldwide distribution of genes found on plasmids and their presence on the chromosomes of aquatic bacteria, such as , one of the suspected sources, suggests an origin before the development of synthetic quinolones. However, their native function remains unknown. Previous work indicated that expression of in was induced by cold shock. To investigate its role further, we constructed single in-frame deletion mutants in and (the gene for cold shock protein) and a double mutant in and in ATCC 17562 to evaluate the response to different environmental conditions and stresses and to exposure to various DNA-damaging agents. We found that is involved in resistance to ciprofloxacin, levofloxacin, and mitomycin C and in the cold shock response in Moreover, Δ and Δ mutants showed slower growth when they were treated with bile salts at 37°C and then shifted to 15°C (cold shock) without bile salts in the medium, with the effect being stronger in the double mutant. This transition may mimic what happens when is ingested into the gastrointestinal tract and released in its natural environment. Cold shock and bile salts induced the expression of and DNA gyrase and topoisomerase IV genes. However, no induction was found in the Δ mutant, suggesting that the gene is involved in the response to DNA damage and nucleic acid secondary structure.
Topics: Bacterial Proteins; Ciprofloxacin; DNA Gyrase; DNA Topoisomerase IV; Quinolones; Vibrio vulnificus
PubMed: 33782008
DOI: 10.1128/AAC.00232-21 -
Biochemistry. Biokhimiia Dec 2009DNA topoisomerases are enzymes responsible for regulation of genomic DNA supercoiling. They participate in essential processes of cells such as replication,... (Review)
Review
DNA topoisomerases are enzymes responsible for regulation of genomic DNA supercoiling. They participate in essential processes of cells such as replication, transcription, recombination, repair, etc., and they are necessary for normal functioning of the cells. Topoisomerases alter the topological state of DNA by either passing one strand of the helix through the other strand (type I) or by passing a region of duplex DNA through another region of duplex DNA (type II). Type I DNA topoisomerases are subdivided into enzymes that bind to the 5'- (type IA) or 3'-phosphate group (type IB) during relaxation of the cleavable DNA. This review summarizes the literature on type IA DNA topoisomerases. Special attention is given to particular properties of their structure and mechanisms of functioning of these enzymes.
Topics: Animals; Archaeal Proteins; Bacterial Proteins; DNA Gyrase; DNA Topoisomerases, Type I; DNA, Superhelical; Humans; Models, Molecular; Nucleic Acid Conformation; Protein Structure, Tertiary
PubMed: 20210704
DOI: 10.1134/s0006297909130045 -
The FEBS Journal Nov 2008Histone-derived antimicrobial peptides have been identified in various organisms from plants to humans. The rat histone H4 mRNA variants, H4-v.1 and rat histogranin...
Histone-derived antimicrobial peptides have been identified in various organisms from plants to humans. The rat histone H4 mRNA variants, H4-v.1 and rat histogranin (HNr) mRNAs, were recently reported to be involved in the synthesis of H4-(86-100) and its related peptide HNr, respectively. Herein, the two peptides were investigated for putative antimicrobial activity and found to inhibit growth of gram-negative (Escherichia coli, Pseudomonas aeruginosa) and gram-positive (Bacillus subtilis, Staphylococcus aureus) bacteria. Their inhibitory potencies in E. coli (LD(50): 3.48 and 4.34 microg x mL(-1)) are comparable to that of the antimicrobial peptide LL-37 (LD(50): 4.10 microg x mL(-1)). The antimicrobial activities of H4-(86-100) and HNr depend upon the integrity of the molecules, as precursors [H4-(84-102), pro-HNr] and fragments [bovine histogranin (HNb)-(1-13), HNb-(3-13), H4-(89-102) or OGP] are at least five times less potent than the parent peptides. Among various HN-like compounds, cyclo-(-Gly-pCl-Phe-Tyr-D-Arg) (compound 3) and N-5-guanidino pentanamide-(2R)-yl-2-N-(p-hydroxyphenylacetyl)-4-(p-chlorobenzoyl)-phenylene diamine (compound 8) display antimicrobial activities comparable to that of HNr. Interestingly, the antimicrobial activities of H4-(86-100), HNr and compound 3, like those of quinolone antibiotics acting as DNA gyrase poisons, are potentiated by ATP (1 mM) and coumermycin A1 (a DNA gyrase-linked ATPase inhibitor) and blocked by 2,4-dinitrophenol (DNP, an uncoupler of oxidative phosphorylation) and fluoroacetic acid (a metabolic poison). Finally, in vitro experiments indicate that H4-(86-100), HNr, compound 3 and compound 8, but not HNb-(1-13) or HNb-(3-13), inhibit DNA gyrase-mediated supercoiling of pBR322 DNA. These data indicate that the naturally occurring H4-(86-100) and HNr display antimicrobial effects that involve a modulation of ATP-dependent DNA gyrase.
Topics: Adenosine Triphosphate; Animals; Anti-Bacterial Agents; DNA Gyrase; Gram-Negative Bacteria; Gram-Positive Bacteria; Histones; Peptide Fragments; Proteins; Rats
PubMed: 18803668
DOI: 10.1111/j.1742-4658.2008.06659.x -
Antimicrobial Agents and Chemotherapy Nov 2002We determined the target enzyme interactions of garenoxacin (BMS-284756, T-3811ME), a novel desfluoroquinolone, in Staphylococcus aureus by genetic and biochemical...
We determined the target enzyme interactions of garenoxacin (BMS-284756, T-3811ME), a novel desfluoroquinolone, in Staphylococcus aureus by genetic and biochemical studies. We found garenoxacin to be four- to eightfold more active than ciprofloxacin against wild-type S. aureus. A single topoisomerase IV or gyrase mutation caused only a 2- to 4-fold increase in the MIC of garenoxacin, whereas a combination of mutations in both loci caused a substantial increase (128-fold). Overexpression of the NorA efflux pump had minimal effect on resistance to garenoxacin. With garenoxacin at twice the MIC, selection of resistant mutants (<7.4 x 10(-12) to 4.0 x 10(-11)) was 5 to 6 log units less than that with ciprofloxacin. Mutations inside or outside the quinolone resistance-determining regions (QRDR) of either topoisomerase IV, or gyrase, or both were selected in single-step mutants, suggesting dual targeting of topoisomerase IV and gyrase. Three of the novel mutations were shown by genetic experiments to be responsible for resistance. Studies with purified topoisomerase IV and gyrase from S. aureus also showed that garenoxacin had similar activity against topoisomerase IV and gyrase (50% inhibitory concentration, 1.25 to 2.5 and 1.25 micro g/ml, respectively), and although its activity against topoisomerase IV was 2-fold greater than that of ciprofloxacin, its activity against gyrase was 10-fold greater. This study provides the first genetic and biochemical data supporting the dual targeting of topoisomerase IV and gyrase in S. aureus by a quinolone as well as providing genetic proof for the expansion of the QRDRs to include the 5' terminus of grlB and the 3' terminus of gyrA.
Topics: Alleles; Anti-Infective Agents; Ciprofloxacin; Cloning, Molecular; DNA Gyrase; DNA Topoisomerase IV; Drug Resistance, Bacterial; Fluoroquinolones; Gene Expression Regulation, Enzymologic; Indoles; Microbial Sensitivity Tests; Mutation; Plasmids; Quinolones; Staphylococcus aureus; Topoisomerase II Inhibitors
PubMed: 12384338
DOI: 10.1128/AAC.46.11.3370-3380.2002 -
Nucleic Acids Research Dec 2016The topological state of DNA is important for replication, recombination and transcription, and is regulated in vivo by DNA topoisomerases. Gyrase introduces negative...
The topological state of DNA is important for replication, recombination and transcription, and is regulated in vivo by DNA topoisomerases. Gyrase introduces negative supercoils into DNA at the expense of ATP hydrolysis. It is the accepted view that gyrase achieves supercoiling by a strand passage mechanism, in which double-stranded DNA is cleaved, and a second double-stranded segment is passed through the gap, converting a positive DNA node into a negative node. We show here that gyrase with only one catalytic tyrosine that cleaves a single strand of its DNA substrate can catalyze DNA supercoiling without strand passage. We propose an alternative mechanism for DNA supercoiling via nicking and closing of DNA that involves trapping, segregation and relaxation of two positive supercoils. In contrast to DNA supercoiling, ATP-dependent relaxation and decatenation of DNA by gyrase lacking the C-terminal domains require both tyrosines and strand passage. Our results point towards mechanistic plasticity of gyrase and might pave the way for finding novel and specific mechanism-based gyrase inhibitors.
Topics: Bacillus subtilis; Catalysis; DNA Gyrase; DNA, Superhelical; Hydrolysis; Models, Molecular; Molecular Conformation; Structure-Activity Relationship; Tyrosine
PubMed: 27557712
DOI: 10.1093/nar/gkw740 -
ACS Infectious Diseases Apr 2024Antimicrobial resistance is a global threat to human health. Therefore, efforts have been made to develop new antibacterial agents that address this critical medical...
Antimicrobial resistance is a global threat to human health. Therefore, efforts have been made to develop new antibacterial agents that address this critical medical issue. Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibacterial in clinical development. Recently, phase III clinical trials for gepotidacin treatment of uncomplicated urinary tract infections caused by uropathogens, including , were stopped for demonstrated efficacy. Because of the clinical promise of gepotidacin, it is important to understand how the compound interacts with its cellular targets, gyrase and topoisomerase IV, from . Consequently, we determined how gyrase and topoisomerase IV mutations in amino acid residues that are involved in gepotidacin interactions affect the susceptibility of cells to the compound and characterized the effects of gepotidacin on the activities of purified wild-type and mutant gyrase and topoisomerase IV. Gepotidacin displayed well-balanced dual-targeting of gyrase and topoisomerase IV in cells, which was reflected in a similar inhibition of the catalytic activities of these enzymes by the compound. Gepotidacin induced gyrase/topoisomerase IV-mediated single-stranded, but not double-stranded, DNA breaks. Mutations in GyrA and ParC amino acid residues that interact with gepotidacin altered the activity of the compound against the enzymes and, when present in both gyrase and topoisomerase IV, reduced the antibacterial activity of gepotidacin against this mutant strain. Our studies provide insights regarding the well-balanced dual-targeting of gyrase and topoisomerase IV by gepotidacin in .
Topics: Acenaphthenes; Amino Acids; Anti-Bacterial Agents; DNA Gyrase; DNA Topoisomerase IV; Escherichia coli; Heterocyclic Compounds, 3-Ring
PubMed: 38606465
DOI: 10.1021/acsinfecdis.3c00346 -
Bioorganic & Medicinal Chemistry May 2020Fluoroquinolones are a class of antibacterial agents used clinically to treat a wide array of bacterial infections and target bacterial type-II topoisomerases (DNA...
Fluoroquinolones are a class of antibacterial agents used clinically to treat a wide array of bacterial infections and target bacterial type-II topoisomerases (DNA gyrase and topoisomerase IV). Fluoroquinolones, however potent, are susceptible to bacterial resistance with prolonged use, which limits their use in the clinic. Quinazoline-2,4-diones also target bacterial type-II topoisomerases and are not susceptible to bacterial resistance similar to fluoroquinolones, however, their potency pales in comparison to fluoroquinolones. To meet the increasing demand for antibacterial development, nine modified quinazoline-2,4-diones were developed to probe quinazoline-2,4-dione structure modification for possible new binding contacts with the bacterial type-II topoisomerase, DNA gyrase. Evaluation of compounds for inhibition of the supercoiling activity of DNA gyrase revealed a novel ethyl 5,6-dihydropyrazolo[1,5-c]quinazoline-1-carboxylate derivative as a modest inhibitor of DNA gyrase, having an IC of 3.5 μM. However, this ethyl 5,6-dihydropyrazolo[1,5-c]quinazoline-1-carboxylate does not trap the catalytic intermediate like fluoroquinolones or typical quinazoline-2,4-diones do. Thus, the ethyl 5,6-dihydropyrazolo[1,5-c]quinazoline-1-carboxylate derivative discovered in this work acts as a catalytic inhibitor of DNA gyrase and therefore represents a new structural type of catalytic inhibitor of DNA gyrase.
Topics: Biocatalysis; DNA Gyrase; Dose-Response Relationship, Drug; Escherichia coli; Molecular Structure; Structure-Activity Relationship; Topoisomerase II Inhibitors
PubMed: 32234278
DOI: 10.1016/j.bmc.2020.115439