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1.
J Med Chem ; 64(12): 8644-8665, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34080858

RESUMO

Due to the poor permeability across Gram-negative bacterial membranes and the troublesome bacterial efflux mechanism, only a few GyrB/ParE inhibitors with potent activity against Gram-negative pathogens have been reported. Among them, pyrimido[4,5-b]indole derivatives represented by GP-1 demonstrated excellent broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria but were limited by hERG inhibition and poor pharmacokinetics profile. To improve their drug-like properties, we designed a series of novel pyrimido[4,5-b]indole derivatives based on the tricyclic scaffold of GP-1 and the C-7 moiety of acorafloxacin. These efforts have culminated in the discovery of a promising compound 18r with reduced hERG liability and an improved PK profile. Compound 18r exhibited superior broad-spectrum in vitro antibacterial activity compared to GP-1, including a variety of clinical multidrug G- pathogens, especially Acinetobacter baumannii, and the in vivo efficacy was also demonstrated in a neutropenic mouse thigh model of infection with multidrug-resistant A. baumannii.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Antibacterianos/uso terapêutico , Bactérias/efeitos dos fármacos , Indóis/uso terapêutico , Pirimidinas/uso terapêutico , Animais , Antibacterianos/síntese química , Antibacterianos/metabolismo , Antibacterianos/farmacocinética , DNA Girase/metabolismo , Desenho de Fármacos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Estabilidade de Medicamentos , Células HEK293 , Humanos , Indóis/síntese química , Indóis/metabolismo , Indóis/farmacocinética , Testes de Sensibilidade Microbiana , Microssomos Hepáticos/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Pirimidinas/síntese química , Pirimidinas/metabolismo , Pirimidinas/farmacocinética , Ratos , Relação Estrutura-Atividade
2.
Acta Chim Slov ; 68(1): 88-101, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34057529

RESUMO

A detailed description of the two new pyridine ligands, (2E,3Z)-3-[2-(3-chloropyridin-2-yl)hydrazinylidene]-N-hydroxybutan-2-imine and 3-chloro-2-(2Z)-2-[1-(4 nitrophenyl)ethylidene]hydrazinyl, is reported. The synthesized compounds were characterized by spectroscopic studies, spectral features were performed by TD-DFT calculations. New-generation pyridine ligand of HL2 was also determinate by single-crystal X-ray diffraction and Hirshfeld surface analysis with two-dimensional fingerprint plots was used to analyze intermolecular interactions in crystals. Molecular-docking was performed to investigate the binding areas of chemical compounds, and the results showed the inhibitory activity of the studied HL1 and HL2 against E. coli. The results of the current study revealed the drug-likeness and bioactive properties of the ligands.


Assuntos
Oximas/química , Piridinas/química , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , DNA Girase/metabolismo , Teoria da Densidade Funcional , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Proteínas de Escherichia coli/metabolismo , Ligantes , Modelos Químicos , Simulação de Acoplamento Molecular , Estrutura Molecular , Oximas/síntese química , Oximas/metabolismo , Oximas/farmacocinética , Ligação Proteica , Piridinas/síntese química , Piridinas/metabolismo , Piridinas/farmacocinética , Difração de Raios X
3.
Nucleic Acids Res ; 49(11): 6027-6042, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-33905522

RESUMO

Type IIA topoisomerases catalyze a variety of different reactions: eukaryotic topoisomerase II relaxes DNA in an ATP-dependent reaction, whereas the bacterial representatives gyrase and topoisomerase IV (Topo IV) preferentially introduce negative supercoils into DNA (gyrase) or decatenate DNA (Topo IV). Gyrase and Topo IV perform separate, dedicated tasks during replication: gyrase removes positive supercoils in front, Topo IV removes pre-catenanes behind the replication fork. Despite their well-separated cellular functions, gyrase and Topo IV have an overlapping activity spectrum: gyrase is also able to catalyze DNA decatenation, although less efficiently than Topo IV. The balance between supercoiling and decatenation activities is different for gyrases from different organisms. Both enzymes consist of a conserved topoisomerase core and structurally divergent C-terminal domains (CTDs). Deletion of the entire CTD, mutation of a conserved motif and even by just a single point mutation within the CTD converts gyrase into a Topo IV-like enzyme, implicating the CTDs as the major determinant for function. Here, we summarize the structural and mechanistic features that make a type IIA topoisomerase a gyrase or a Topo IV, and discuss the implications for type IIA topoisomerase evolution.


Assuntos
DNA Girase/química , DNA Topoisomerase IV/química , Bactérias/enzimologia , DNA/química , DNA/metabolismo , DNA Girase/genética , DNA Girase/metabolismo , DNA Topoisomerase IV/genética , DNA Topoisomerase IV/metabolismo , DNA Topoisomerases Tipo II/química , Evolução Molecular , Conformação Proteica , Domínios Proteicos
4.
Proc Natl Acad Sci U S A ; 118(11)2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33836580

RESUMO

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.


Assuntos
Proteínas de Bactérias/metabolismo , DNA Girase/metabolismo , Mimetismo Molecular , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Mycobacterium/enzimologia , Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/química , Cristalografia por Raios X , Clivagem do DNA , Proteínas Monoméricas de Ligação ao GTP/química , Conformação Proteica
5.
Bioorg Chem ; 111: 104885, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33838559

RESUMO

New antibacterial drugs are urgently needed to tackle the rapid rise in multi-drug resistant bacteria. DNA gyrase is a validated target for the development of new antibacterial drugs. Thus, in the present investigation, a novel series of 1,2,4-oxadiazole-chalcone/oxime (6a-f) and (7a-f) were synthesized and characterized by IR, NMR (1H and 13C) and elemental analyses. The title compounds were evaluated for their in-vitro antimicrobial activity by the modified agar diffusion method as well as their E. coli DNA gyrase inhibitory activity. The minimum inhibitory concentration (MIC) and the structure activity relationships (SARs) were evaluated. Among all, compounds 6a, 6c-e, 7b and 7e were the most potent and proved to possess broad spectrum activity against the tested Gram-positive and Gram-negative organisms. Additionally, compounds 6a (against S. aureus), 6c (against B. subtilis and E. hirae), 6e (against E. hirae), 6f, 7a and 7c (against E. coli) and 7d (against B. subtilis), with MIC value of 3.12 µM were two-fold more potent than the standard ciprofloxacin (MIC = 6.25 µM). Mechanistically, compounds 6c, 7c, 7e and 7b had good inhibitory activity against E. coli gyrase with IC50 values of 17.05, 13.4, 16.9, and 19.6 µM, respectively, in comparison with novobiocin (IC50 = 12.3 µM) and ciprofloxacin (IC50 = 10.5 µM). The molecular docking results at DNA gyrase active site revealed that the most potent compounds 6c and 7c have binding mode and docking scores comparable to that of ciprofloxacin and novobiocin suggesting their antibacterial activity via inhibition of DNA gyrase. Finally, the predicted parameters of Lipinski's rule of five and ADMET analysis showed that 6c and 7c had good drug-likeness and acceptable physicochemical properties. Therefore, the hybridization of the chalcone and oxadiazole moieties could be promising lead as antibacterial candidate which merit further future structural optimizations.


Assuntos
Antibacterianos/farmacologia , DNA Girase/metabolismo , Desenho de Fármacos , Simulação de Acoplamento Molecular , Inibidores da Topoisomerase II/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Bacillus subtilis/efeitos dos fármacos , Relação Dose-Resposta a Droga , Enterococcus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-Atividade , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/química
6.
J Med Chem ; 64(9): 6329-6357, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33929852

RESUMO

Herein, we describe the discovery and optimization of a novel series that inhibits bacterial DNA gyrase and topoisomerase IV via binding to, and stabilization of, DNA cleavage complexes. Optimization of this series led to the identification of compound 25, which has potent activity against Gram-positive bacteria, a favorable in vitro safety profile, and excellent in vivo pharmacokinetic properties. Compound 25 was found to be efficacious against fluoroquinolone-sensitive Staphylococcus aureus infection in a mouse thigh model at lower doses than moxifloxacin. An X-ray crystal structure of the ternary complex formed by topoisomerase IV from Klebsiella pneumoniae, compound 25, and cleaved DNA indicates that this compound does not engage in a water-metal ion bridge interaction and forms no direct contacts with residues in the quinolone resistance determining region (QRDR). This suggests a structural basis for the reduced impact of QRDR mutations on antibacterial activity of 25 compared to fluoroquinolones.


Assuntos
Antibacterianos/farmacologia , DNA Girase/metabolismo , DNA Topoisomerase IV/antagonistas & inibidores , Desenho de Fármacos , Fluoroquinolonas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Inibidores da Topoisomerase II/farmacologia , Animais , Antibacterianos/química , Farmacorresistência Bacteriana/efeitos dos fármacos , Camundongos , Inibidores da Topoisomerase II/química
7.
Eur J Clin Microbiol Infect Dis ; 40(8): 1599-1608, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33646449

RESUMO

In China, there is a high prevalence of antibiotic-resistant Helicobacter pylori infections in the population. The aim of the study was to assess a new ARMS-PCR test for detection of H. pylori clarithromycin resistance (CR) and quinolone resistance (QR) mutations and evaluate the spectrum of antibiotic resistance in patients from three Chinese provinces. Sanger sequencing and multiplex ARMS-PCR were used to detect H. pylori CR and QR bacteria in gastric biopsy samples. Among the 1,182 patients enrolled with gastritis, 643 (54.4%) were positive for H. pylori. Of these, 371 (57.7%) had antibiotic-resistant strains, comprising 236 (63.6%) with a single drug antibiotic-resistant strain and 135 (36.4%) with multiple drug-resistant strains. Following Sanger sequencing analysis of 23S rRNA and gyrA gene for mutations (antibiotic resistance markers), rates of CR, QR, and multidrug resistance (CR and QR) were 19.9, 12.0, and 25.8%, respectively. The 23S rRNA CR mutation A2143G (286, 96.9%) and the gyrA QR mutations C261A (85, 31.5%) and G271A (71, 26.3%) were common. Benchmarking against Sanger sequencing results, multiplex ARMS-PCR test had a high diagnostic sensitivity and specificity for detection of CR (96 and 93%), QR (95 and 92%) and multidrug resistance (95 and 95%). Based on our findings, the high incidence of single and multiple antibiotic resistance requires the routine checking of antibiotic resistance in all patients with suspected H. pylori infections. Multiplex ARMS-PCR is a simple and rapid test that can be now used for more efficient treatment of H. pylori infections and reduces the misuse of antibiotics.


Assuntos
Antibacterianos/farmacologia , Claritromicina/farmacologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , Quinolonas/farmacologia , Adulto , China/epidemiologia , DNA Girase/genética , DNA Girase/metabolismo , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/genética , Humanos , Masculino , Pessoa de Meia-Idade , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética
8.
Molecules ; 26(5)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33669078

RESUMO

Gyrase is a bacterial type IIA topoisomerase that catalyzes negative supercoiling of DNA. The enzyme is essential in bacteria and is a validated drug target in the treatment of bacterial infections. Inhibition of gyrase activity is achieved by competitive inhibitors that interfere with ATP- or DNA-binding, or by gyrase poisons that stabilize cleavage complexes of gyrase covalently bound to the DNA, leading to double-strand breaks and cell death. Many of the current inhibitors suffer from severe side effects, while others rapidly lose their antibiotic activity due to resistance mutations, generating an unmet medical need for novel, improved gyrase inhibitors. DNA supercoiling by gyrase is associated with a series of nucleotide- and DNA-induced conformational changes, yet the full potential of interfering with these conformational changes as a strategy to identify novel, improved gyrase inhibitors has not been explored so far. This review highlights recent insights into the mechanism of DNA supercoiling by gyrase and illustrates the implications for the identification and development of conformation-sensitive and allosteric inhibitors.


Assuntos
DNA Girase/metabolismo , Inibidores da Topoisomerase II/farmacologia , Bactérias/enzimologia , Modelos Moleculares , Inibidores da Topoisomerase II/química
9.
Eur J Clin Microbiol Infect Dis ; 40(8): 1767-1771, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33604720

RESUMO

In this study, we demonstrate that fluroquinolone (FQ) is at risk of acquired drug resistance after continuous exposure. The reduced susceptibility is observed in subsequent Mycobacterium tuberculosis isolates from patients without FQ exposure. The stepwise selection of mutation of increasing FQ resistance highlights the urgent need for monitoring FQ resistance in multidrug-resistant tuberculosis patients throughout the entire treatment course.


Assuntos
Antituberculosos/farmacologia , Moxifloxacina/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Estudos de Coortes , DNA Girase/genética , DNA Girase/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Fluoroquinolonas/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Mutação , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Estudos Retrospectivos , Seleção Genética
10.
J Biol Chem ; 296: 100451, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33626388

RESUMO

Deinococcus radiodurans harbors a multipartite ploid genome system consisting of two chromosomes and two plasmids present in multiple copies. How these discrete genome elements are maintained and inherited is not well understood. PprA, a pleiotropic protein involved in radioresistance, has been characterized for its roles in DNA repair, genome segregation, and cell division in this bacterium. Here, we show that PprA regulates ploidy of chromosome I and II and inhibits the activity of drDnaA, the initiator protein in D. radiodurans. We found that pprA deletion resulted in an increased genomic content and ploidy of both the chromosomal elements. Expression of PprA in trans rescued the phenotypes of the pprA mutant. To understand the molecular mechanism underlying these phenotypes, we characterized drDnaA and drDnaB. As expected for an initiator protein, recombinant drDnaA showed sequence-specific interactions with the putative oriC sequence in chromosome I (oriCI). Both drDnaA and drDnaB showed ATPase activity, also typical of initiator proteins, but only drDnaB exhibited 5'→3' dsDNA helicase activity in vitro. drDnaA and drDnaB showed homotypic and heterotypic interactions with each other, which were perturbed by PprA. Interestingly, PprA has inhibited the ATPase activity of drDnaA but showed no effect on the activity of drDnaB. Regulation of chromosome copy number and inhibition of the initiator protein functions by PprA strongly suggest that it plays a role as a checkpoint regulator of the DNA replication initiation in D. radiodurans perhaps through its interaction with the replication initiation machinery.


Assuntos
Deinococcus/genética , Deinococcus/metabolismo , Proteínas de Bactérias/metabolismo , Divisão Celular/genética , Segregação de Cromossomos , DNA Girase/metabolismo , Reparo do DNA/genética , Replicação do DNA/genética , Genoma Bacteriano/genética , Plasmídeos/genética , Ploidias , Domínios e Motivos de Interação entre Proteínas , Tolerância a Radiação
11.
Eur J Med Chem ; 213: 113200, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33524686

RESUMO

The rise in multidrug-resistant bacteria defines the need for identification of new antibacterial agents that are less prone to resistance acquisition. Compounds that simultaneously inhibit multiple bacterial targets are more likely to suppress the evolution of target-based resistance than monotargeting compounds. The structurally similar ATP binding sites of DNA gyrase and topoisomerase Ⅳ offer an opportunity to accomplish this goal. Here we present the design and structure-activity relationship analysis of balanced, low nanomolar inhibitors of bacterial DNA gyrase and topoisomerase IV that show potent antibacterial activities against the ESKAPE pathogens. For inhibitor 31c, a crystal structure in complex with Staphylococcus aureus DNA gyrase B was obtained that confirms the mode of action of these compounds. The best inhibitor, 31h, does not show any in vitro cytotoxicity and has excellent potency against Gram-positive (MICs: range, 0.0078-0.0625 µg/mL) and Gram-negative pathogens (MICs: range, 1-2 µg/mL). Furthermore, 31h inhibits GyrB mutants that can develop resistance to other drugs. Based on these data, we expect that structural derivatives of 31h will represent a step toward clinically efficacious multitargeting antimicrobials that are not impacted by existing antimicrobial resistance.


Assuntos
Trifosfato de Adenosina/farmacologia , Antibacterianos/farmacologia , DNA Girase/metabolismo , DNA Topoisomerase IV/antagonistas & inibidores , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Trifosfato de Adenosina/síntese química , Trifosfato de Adenosina/química , Antibacterianos/síntese química , Antibacterianos/química , Cristalografia por Raios X , DNA Topoisomerase IV/metabolismo , Relação Dose-Resposta a Droga , Escherichia coli/enzimologia , Escherichia coli/patogenicidade , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Staphylococcus aureus/enzimologia , Staphylococcus aureus/patogenicidade , Relação Estrutura-Atividade
12.
Eur J Med Chem ; 216: 113293, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33640673

RESUMO

Compounds incorporating guanidine moieties constitute a versatile class of biologically interesting molecules with a wide array of applications. As such, guanidines have been exploited as privileged structural motifs in designing novel drugs for the treatment of various infectious and non-infectious diseases. In designing anti-infective agents, this moiety carries great appeal by virtue of attributes such as hydrogen-bonding capability and protonatability at physiological pH in the context of interaction with biological targets. This review provides an overview of recent advances in hit-to-lead development studies of antimicrobial guanidine-containing compounds with the aim to highlight their structural diversity and the pharmacological relevance of the moiety to drug activity, insofar as possible. In so doing, emphasis is put on chemical and microbiological properties of such compounds in relation to antibacterial, antifungal and antimalarial activities.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Sítios de Ligação , DNA Girase/química , DNA Girase/metabolismo , Desenho de Fármacos , Fungos/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Guanidina/química , Guanidina/metabolismo , Guanidina/farmacologia , Testes de Sensibilidade Microbiana , Simulação de Dinâmica Molecular , Relação Estrutura-Atividade
13.
Nat Commun ; 12(1): 150, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420011

RESUMO

Novel bacterial type II topoisomerase inhibitors (NBTIs) stabilize single-strand DNA cleavage breaks by DNA gyrase but their exact mechanism of action has remained hypothetical until now. We have designed a small library of NBTIs with an improved DNA gyrase-binding moiety resulting in low nanomolar inhibition and very potent antibacterial activity. They stabilize single-stranded cleavage complexes and, importantly, we have obtained the crystal structure where an NBTI binds gyrase-DNA in a single conformation lacking apparent static disorder. This directly proves the previously postulated NBTI mechanism of action and shows that they stabilize single-strand cleavage through asymmetric intercalation with a shift of the scissile phosphate. This crystal stucture shows that the chlorine forms a halogen bond with the backbone carbonyls of the two symmetry-related Ala68 residues. To the best of our knowledge, such a so-called symmetrical bifurcated halogen bond has not been identified in a biological system until now.


Assuntos
Antibacterianos/farmacologia , Cloro/metabolismo , DNA Girase/metabolismo , Inibidores da Topoisomerase II/farmacologia , Alanina/química , Alanina/metabolismo , Antibacterianos/química , Cristalografia por Raios X , DNA Girase/química , DNA Topoisomerases Tipo II , DNA de Cadeia Simples/metabolismo , Desenho de Fármacos , Canal de Potássio ERG1/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Células Hep G2 , Células Endoteliais da Veia Umbilical Humana , Humanos , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Proteínas de Ligação a Poli-ADP-Ribose/antagonistas & inibidores , Quinolinas/química , Quinolinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Inibidores da Topoisomerase II/química
14.
Nucleic Acids Res ; 49(3): 1581-1596, 2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33434265

RESUMO

DNA gyrase, a type II topoisomerase found predominantly in bacteria, is the target for a variety of 'poisons', namely natural product toxins (e.g. albicidin, microcin B17) and clinically important synthetic molecules (e.g. fluoroquinolones). Resistance to both groups can be mediated by pentapeptide repeat proteins (PRPs). Despite long-term studies, the mechanism of action of these protective PRPs is not known. We show that a PRP, QnrB1 provides specific protection against fluoroquinolones, which strictly requires ATP hydrolysis by gyrase. QnrB1 binds to the GyrB protein and stimulates ATPase activity of the isolated N-terminal ATPase domain of GyrB (GyrB43). We probed the QnrB1 binding site using site-specific incorporation of a photoreactive amino acid and mapped the crosslinks to the GyrB43 protein. We propose a model in which QnrB1 binding allosterically promotes dissociation of the fluoroquinolone molecule from the cleavage complex.


Assuntos
Proteínas de Bactérias/metabolismo , DNA Girase/metabolismo , Inibidores da Topoisomerase II/toxicidade , Trifosfato de Adenosina/metabolismo , Bacteriocinas/toxicidade , Ciprofloxacina/toxicidade , DNA/metabolismo , Escherichia coli/enzimologia , Hidrólise , Compostos Orgânicos/toxicidade , Xanthomonas
15.
Biomed Pharmacother ; 134: 111132, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360050

RESUMO

DNA gyrase and Topoisomerase IV are promising antibacterial drug targets as they regulate bacterial DNA replication and topology. In a quest for novel DNA topoisomerase inhibitors, a multidisciplinary approach was adopted that involves computational prediction of binding sites and molecular modelling followed by green synthesis and biological evaluation of antibacterial activity of spirobenzimidazo quinazolines derivatives. Using basic quantum chemistry principles, we evaluated spirobenzimidazo quinazolines derivatives with their pharmacokinetic profiles. Based on the results of the aforesaid in-silico studies, we synthesized a series of titled compounds using green synthetic methodology that were validated as potential antimicrobial agents. Quantum chemoinformatics based predicted activity for the synthesized compounds 9b, 9c, and 9j was concomitant with biological evaluation of broadspectrum antibacterial activity. Biological evaluation revealed that inhibition of biofilm formation was due to their potential antibacterial activity. We believe that the novel spirobenzimidazo quinazolines have the potential to be alternatives to aminocoumarins and classical quinazolines upon detailed target specific biological studies.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Benzimidazóis/farmacologia , Desenho Assistido por Computador , DNA Girase/metabolismo , Desenho de Fármacos , Quinazolinas/farmacologia , Inibidores da Topoisomerase II/farmacologia , Antibacterianos/síntese química , Bactérias/crescimento & desenvolvimento , Benzimidazóis/síntese química , Sítios de Ligação , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , DNA Girase/química , Química Verde , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Ligação Proteica , Relação Quantitativa Estrutura-Atividade , Quinazolinas/síntese química , Inibidores da Topoisomerase II/síntese química
16.
PLoS One ; 15(11): e0241780, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33141832

RESUMO

The DNA topoisomerase complement of Streptococcus pneumoniae is constituted by two type II enzymes (topoisomerase IV and gyrase), and a single type I enzyme (topoisomerase I). These enzymes maintain the DNA topology, which is essential for replication and transcription. While fluoroquinolones target the type II enzymes, seconeolitsine, a new antimicrobial agent, targets topoisomerase I. We compared for the first time the in vitro effect of inhibition of topoisomerase I by seconeolitsine and of the type II topoisomerases by the fluoroquinolones levofloxacin and moxifloxacin. We used three isogenic non-encapsulated strains and five non-vaccine serotypes isolates belonging to two circulating pneumococcal clones, ST638 (2 strains) and ST1569V (3 strains). Each group contained strains with diverse susceptibility to fluoroquinolones. Minimal inhibitory concentrations, killing curves and postantibiotic effects were determined. Seconeolitsine demonstrated the fastest and highest bactericidal activity against planktonic bacteria and biofilms. When fluoroquinolone-susceptible planktonic bacteria were considered, seconeolitsine induced postantibiotic effects (1.00-1.87 h) similar than levofloxacin (1.00-2.22 h), but longer than moxifloxacin (0.39-1.71 h). The same effect was observed in sessile bacteria forming biofilms. Seconeolitsine induced postantibiotic effects (0.84-2.31 h) that were similar to those of levofloxacin (0.99-3.32 h) but longer than those of moxifloxacin (0.89-1.91 h). The greatest effect was observed in the viability and adherence of bacteria in the postantibiotic phase. Seconeolitsine greatly reduced the thickness of the biofilms formed in comparison with fluoroquinolones: 2.91 ± 0.43 µm (seconeolitsine), 7.18 ± 0.58 µm (levofloxacin), 17.08 ± 1.02 µm (moxifloxacin). When fluoroquinolone-resistant bacteria were considered, postantibiotic effects induced by levofloxacin and moxifloxacin, but not by seconeolitsine, were shorter, decreasing up to 5-fold (levofloxacin) or 2-fold (moxifloxacin) in planktonic cells, and up to 1.7 (levofloxacin) or 1.4-fold (moxifloxacin) during biofilm formation. Therefore, topoisomerase I inhibitors could be an alternative for the treatment of pneumococcal diseases, including those caused by fluoroquinolone-resistant isolates.


Assuntos
Antibacterianos/farmacologia , DNA Topoisomerase IV/antagonistas & inibidores , Fluoroquinolonas/farmacologia , Streptococcus pneumoniae/efeitos dos fármacos , Inibidores da Topoisomerase I/farmacologia , Benzodioxóis/farmacologia , DNA Girase/metabolismo , Levofloxacino/farmacologia , Moxifloxacina/farmacologia , Fenantrenos/farmacologia , Streptococcus pneumoniae/enzimologia
17.
Bioorg Chem ; 105: 104387, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33130344

RESUMO

7H-Benzo[7,8]chromeno[2,3-d]pyrimidin-9(8H)-amine (6a,b) have been synthesized via hydrazinolysis of the imidates (5a,b). Polysubstituted chromenotriazolopyrimidine (7a-j), (12a,b) and Schiff base (8a,b) derivatives have also been prepared. The new heterocyclic derivatives were affirmed by spectral data. The target compounds have been screened for antibacterial and antifungal activity. Compounds 6a,b and 7a-c, g,h displayed the most favorable antimicrobial activities in resemblance to the reference antimicrobial agents by IZ range over 24 mm. In addition, MIC, MBC and MFC were also tested and screen for most active compound 6a by 6.25 µg/mL showing bactericidal effect. SAR study revealed that the antimicrobial vitality of the target compounds was safely influenced by the lipophilicity substituents and the calculated log P value. The potent compounds were subjected into in vitro enzyme screening (14α-Demethylase and DNA Gyrase) against both interesting targets and showed good inhibitory profile. Molecular modeling analyses were introduced and discussed focusing on the docking of active compounds into two essential targets, and their ADMET properties were studied.


Assuntos
Inibidores de 14-alfa Desmetilase/farmacologia , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Benzopiranos/farmacologia , Inibidores da Topoisomerase II/farmacologia , Inibidores de 14-alfa Desmetilase/síntese química , Inibidores de 14-alfa Desmetilase/química , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Aspergillus/efeitos dos fármacos , Benzopiranos/síntese química , Benzopiranos/química , Candida albicans/efeitos dos fármacos , DNA Girase/metabolismo , Relação Dose-Resposta a Droga , Bactérias Gram-Positivas/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Esterol 14-Desmetilase/metabolismo , Relação Estrutura-Atividade , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/química
18.
BMC Infect Dis ; 20(1): 866, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33213390

RESUMO

BACKGROUND: Mycolicibacterium fortuitum is a species of the rapidly growing mycobacteria that can cause pulmonary infection. It is susceptible to multiple antibiotics both in vitro and in clinical practice, so that any combination of susceptible drugs is effective. However, we encountered a case of infection due to fluoroquinolone-resistant M. fortuitum. In this study, we report the case and describe the mechanism of resistance. CASE PRESENTATION: A 65-year-old man with a history of total gastrectomy and immunosuppressant treatment for rheumatoid arthritis developed a recurrence of pulmonary infection caused by M. fortuitum. He was treated with clarithromycin and levofloxacin as a first-line treatment, based on the favorable susceptibility at that time. After recurrence, a high minimum inhibitory concentration to fluoroquinolones was detected. DNA sequencing of the pathogen showed the substitution of serine for tryptophan at residue 83 in the gyrA gene. He was successfully treated with a combination of other antibiotics. CONCLUSION: This is the first report on the treatment of fluoroquinolone-resistant M. fortuitum and investigation of the mechanism of resistance. We suggest that the susceptibility test remains effective for determining the next line of treatment after a pathogen has acquired resistance, and resistance to fluoroquinolones in M. fortuitum can be attributed to a single change of amino acid.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Fluoroquinolonas/farmacologia , Pneumopatias/diagnóstico , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Mycobacterium fortuitum/efeitos dos fármacos , Idoso , Substituição de Aminoácidos , DNA Girase/química , DNA Girase/genética , DNA Girase/metabolismo , Humanos , Pneumopatias/microbiologia , Masculino , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/microbiologia , Mycobacterium fortuitum/genética , Mycobacterium fortuitum/isolamento & purificação , Recidiva , Análise de Sequência de DNA
19.
Mol Biol Rep ; 47(12): 9615-9625, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33190200

RESUMO

Antimicrobial resistance is increasing around the world and the search for effective treatment options, such as new antibiotics and combination therapy is urgently needed. The present study evaluates oregano essential oil (OEO) antibacterial activities against reference and multidrug-resistant clinical isolates of Acinetobacter baumannii (Ab-MDR). Additionally, the combination of the OEO and polymyxin B was evaluated against Ab-MDR. Ten clinical isolates were characterized at the species level through multiplex polymerase chain reaction (PCR) for the gyrB and blaOXA-51-like genes. The isolates were resistant to at least four different classes of antimicrobial agents, namely, aminoglycosides, cephems, carbapenems, and fluoroquinolones. All isolates were metallo-ß-lactamase (MßL) and carbapenemase producers. The major component of OEO was found to be carvacrol (71.0%) followed by ß-caryophyllene (4.0%), γ-terpinene (4.5%), p-cymene (3,5%), and thymol (3.0%). OEO showed antibacterial effect against all Ab-MDR tested, with minimum inhibitory concentrations (MIC) ranging from 1.75 to 3.50 mg mL-1. Flow cytometry demonstrated that the OEO causes destabilization and rupture of the bacterial cell membrane resulting in apoptosis of A. baumannii cells (p < 0.05). Synergic interaction between OEO and polymyxin B (FICI: 0.18 to 0.37) was observed, using a checkerboard assay. When combined, OEO presented until 16-fold reduction of the polymyxin B MIC. The results presented here indicate that the OEO used alone or in combination with polymyxin B in the treatment of Ab-MDR infections is promising. To the best of our knowledge, this is the first report of OEO and polymyxin B association against Ab-MDR clinical isolates.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Óleos Voláteis/farmacologia , Origanum/química , Polimixina B/farmacologia , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/crescimento & desenvolvimento , Aminoglicosídeos/farmacologia , Antibacterianos/isolamento & purificação , Carbapenêmicos/farmacologia , Cefalosporinas/farmacologia , Cimenos/isolamento & purificação , Cimenos/farmacologia , DNA Girase/genética , DNA Girase/metabolismo , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla/genética , Sinergismo Farmacológico , Fluoroquinolonas/farmacologia , Expressão Gênica , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Sesquiterpenos Policíclicos/isolamento & purificação , Sesquiterpenos Policíclicos/farmacologia , beta-Lactamases/genética , beta-Lactamases/metabolismo
20.
Biochem J ; 477(21): 4167-4190, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33030198

RESUMO

Drug repurposing is an alternative avenue for identifying new drugs to treat tuberculosis (TB). Despite the broad-range of anti-tubercular drugs, the emergence of multi-drug-resistant and extensively drug-resistant strains of Mycobacterium tuberculosis (Mtb) H37Rv, as well as the significant death toll globally, necessitates the development of new and effective drugs to treat TB. In this study, we have employed a drug repurposing approach to address this drug resistance problem by screening the drugbank database to identify novel inhibitors of the Mtb target enzyme, DNA gyrase. The compounds were screened against the ATPase domain of the gyrase B subunit (MtbGyrB47), and the docking results showed that echinacoside, doxorubicin, epirubicin, and idarubicin possess high binding affinities against MtbGyrB47. Comprehensive assessment using fluorescence spectroscopy, surface plasmon resonance spectroscopy (SPR), and circular dichroism (CD) titration studies revealed echinacoside as a potent binder of MtbGyrB47. Furthermore, ATPase, and DNA supercoiling assays exhibited an IC50 values of 2.1-4.7 µM for echinacoside, doxorubicin, epirubicin, and idarubicin. Among these compounds, the least MIC90 of 6.3 and 12 µM were observed for epirubicin and echinacoside, respectively, against Mtb. Our findings indicate that echinacoside and epirubicin targets mycobacterial DNA gyrase, inhibit its catalytic cycle, and retard mycobacterium growth. Further, these compounds exhibit potential scaffolds for optimizing novel anti-mycobacterial agents that can act on drug-resistant strains.


Assuntos
Antituberculosos/farmacologia , DNA Girase/metabolismo , Mycobacterium tuberculosis/enzimologia , Adenosina Trifosfatases/metabolismo , Antituberculosos/química , Dicroísmo Circular , Doxorrubicina/química , Doxorrubicina/farmacologia , Desenho de Fármacos , Reposicionamento de Medicamentos/métodos , Epirubicina/química , Epirubicina/farmacologia , Glicosídeos/química , Glicosídeos/farmacologia , Idarubicina/química , Idarubicina/farmacologia , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Relação Estrutura-Atividade , Ressonância de Plasmônio de Superfície , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/farmacologia
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