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1.
Int J Mol Sci ; 25(10)2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38791189

RESUMO

The membrane Fo factor of ATP synthase is highly sensitive to mutations in the proton half-channel leading to the functional blocking of the entire protein. To identify functionally important amino acids for the proton transport, we performed molecular dynamic simulations on the selected mutants of the membrane part of the bacterial FoF1-ATP synthase embedded in a native lipid bilayer: there were nine different mutations of a-subunit residues (aE219, aH245, aN214, aQ252) in the inlet half-channel. The structure proved to be stable to these mutations, although some of them (aH245Y and aQ252L) resulted in minor conformational changes. aH245 and aN214 were crucial for proton transport as they directly facilitated H+ transfer. The substitutions with nonpolar amino acids disrupted the transfer chain and water molecules or neighboring polar side chains could not replace them effectively. aE219 and aQ252 appeared not to be determinative for proton translocation, since an alternative pathway involving a chain of water molecules could compensate the ability of H+ transmembrane movement when they were substituted. Thus, mutations of conserved polar residues significantly affected hydration levels, leading to drastic changes in the occupancy and capacity of the structural water molecule clusters (W1-W3), up to their complete disappearance and consequently to the proton transfer chain disruption.


Assuntos
ATPases Bacterianas Próton-Translocadoras , Simulação de Dinâmica Molecular , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Mutação , Conformação Proteica , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , ATPases Bacterianas Próton-Translocadoras/química , ATPases Bacterianas Próton-Translocadoras/genética
2.
Elife ; 112022 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-35107420

RESUMO

In FoF1-ATP synthase, proton translocation through Fo drives rotation of the c-subunit oligomeric ring relative to the a-subunit. Recent studies suggest that in each step of the rotation, key glutamic acid residues in different c-subunits contribute to proton release to and proton uptake from the a-subunit. However, no studies have demonstrated cooperativity among c-subunits toward FoF1-ATP synthase activity. Here, we addressed this using Bacillus PS3 ATP synthase harboring a c-ring with various combinations of wild-type and cE56D, enabled by genetically fused single-chain c-ring. ATP synthesis and proton pump activities were decreased by a single cE56D mutation and further decreased by double cE56D mutations. Moreover, activity further decreased as the two mutation sites were separated, indicating cooperation among c-subunits. Similar results were obtained for proton transfer-coupled molecular simulations. The simulations revealed that prolonged proton uptake in mutated c-subunits is shared between two c-subunits, explaining the cooperation observed in biochemical assays.


Cells need to be able to store and transfer energy to fuel their various activities. To do this, they produce a small molecule called ATP to carry the energy, which is then released when the ATP is broken down. An enzyme found in plants, animals and bacteria, called FoF1 ATP synthase, can both create and use ATP. When it does this, protons, or positive hydrogen ions, are transported across cellular boundaries called membranes. The region of the enzyme that is responsible for pumping the protons contains different parts known as the c-ring and the a-subunit. The movement of protons drives the c-ring to rotate relative to the a-subunit, which leads to producing ATP. Previous research using simulations and the protein structures found there are two or three neighbouring amino acids in the c-ring that face the a-subunit, suggesting that these amino acids act together to drive the rotation. To test this hypothesis, Mitome et al. mutated these amino acids to examine the effect on the enzyme's ability to produce ATP. A single mutation reduced the production of ATP, which decreased even further with mutations in two of the amino acids. The extent of this decrease depended on the distance between the two mutations in the c-ring. Simulations of these changes also found similar results. This indicates there is coordination between different parts of the c-ring to increase the rate of ATP production. This study offers new insights into the molecular processes controlling ATP synthesis and confirms previous theoretical research. This will interest specialists in bioenergetics because it addresses a fundamental biological question with broad impact.


Assuntos
ATPases Bacterianas Próton-Translocadoras/química , ATPases Bacterianas Próton-Translocadoras/metabolismo , Prótons , Bacillus , ATPases Bacterianas Próton-Translocadoras/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Simulação de Dinâmica Molecular , Mutação , Conformação Proteica
3.
Sci Rep ; 11(1): 21234, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34707181

RESUMO

Membrane bound nicotinamide nucleotide transhydrogenase (TH) catalyses the hydride transfer from NADH to NADP+. Under physiological conditions, this reaction is endergonic and must be energized by the pmf, coupled to transmembrane proton transport. Recent structures of transhydrogenase holoenzymes suggest new mechanistic details, how the long-distance coupling between hydride transfer in the peripheral nucleotide binding sites and the membrane-localized proton transfer occurs that now must be tested experimentally. Here, we provide protocols for the efficient expression and purification of the Escherichia coli transhydrogenase and its reconstitution into liposomes, alone or together with the Escherichia coli F1F0 ATP synthase. We show that E. coli transhydrogenase is a reversible enzyme that can also work as a NADPH-driven proton pump. In liposomes containing both enzymes, NADPH driven H+-transport by TH is sufficient to instantly fuel ATP synthesis, which adds TH to the pool of pmf generating enzymes. If the same liposomes are energized with ATP, NADPH production by TH is stimulated > sixfold both by a pH gradient or a membrane potential. The presented protocols and results reinforce the tight coupling between hydride transfer in the peripheral nucleotide binding sites and transmembrane proton transport and provide powerful tools to investigate their coupling mechanism.


Assuntos
ATPases Bacterianas Próton-Translocadoras/metabolismo , Transferência de Energia , Proteínas de Escherichia coli/metabolismo , NADP Trans-Hidrogenases/metabolismo , Trifosfato de Adenosina/metabolismo , ATPases Bacterianas Próton-Translocadoras/química , Proteínas de Escherichia coli/química , Transporte de Íons , Lipossomos/metabolismo , NADP Trans-Hidrogenases/química
4.
Nat Commun ; 12(1): 4690, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344897

RESUMO

F1Fo ATP synthase interchanges phosphate transfer energy and proton motive force via a rotary catalysis mechanism. Isolated F1-ATPase catalytic cores can hydrolyze ATP, passing through six intermediate conformational states to generate rotation of their central γ-subunit. Although previous structural studies have contributed greatly to understanding rotary catalysis in the F1-ATPase, the structure of an important conformational state (the binding-dwell) has remained elusive. Here, we exploit temperature and time-resolved cryo-electron microscopy to determine the structure of the binding- and catalytic-dwell states of Bacillus PS3 F1-ATPase. Each state shows three catalytic ß-subunits in different conformations, establishing the complete set of six states taken up during the catalytic cycle and providing molecular details for both the ATP binding and hydrolysis strokes. We also identify a potential phosphate-release tunnel that indicates how ADP and phosphate binding are coordinated during synthesis. Overall these findings provide a structural basis for the entire F1-ATPase catalytic cycle.


Assuntos
ATPases Bacterianas Próton-Translocadoras/química , Difosfato de Adenosina/química , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/química , Trifosfato de Adenosina/metabolismo , Bacillus/enzimologia , ATPases Bacterianas Próton-Translocadoras/genética , ATPases Bacterianas Próton-Translocadoras/metabolismo , Sítios de Ligação , Catálise , Microscopia Crioeletrônica , Hidrólise , Mutação , Fosfatos/química , Fosfatos/metabolismo , Ligação Proteica , Conformação Proteica , Subunidades Proteicas , Rotação , Temperatura
5.
Anal Biochem ; 616: 114088, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33358938

RESUMO

Endosomal escape is considered a crucial barrier that needs to be overcome by integrin-mediated E. coli for gene delivery into mammalian cells. Bafilomycin, a potent inhibitor of the H+ proton pump commonly employed to lower endosomal pH, was evaluated as part of the E. coli protocol during delivery. We found an increase in green fluorescent protein expression up 6.9, 3.2, 5.0, 2.8, and 4.5 fold in HeLa, HEK-293, A549, HT1080, and MCF-7 respectively, compared to untreated cells. Our result showed for the first time that Inhibition of lysosomal V-ATPase enhances E. coli efficiency.


Assuntos
ATPases Bacterianas Próton-Translocadoras/antagonistas & inibidores , Escherichia coli/enzimologia , Lisossomos/enzimologia , ATPases Vacuolares Próton-Translocadoras/antagonistas & inibidores , Linhagem Celular Transformada , Linhagem Celular Tumoral , Regulação para Baixo/efeitos dos fármacos , Escherichia coli/genética , Vetores Genéticos/metabolismo , Proteínas de Fluorescência Verde/biossíntese , Homeostase/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Lisossomos/efeitos dos fármacos , Macrolídeos/farmacologia , Transfecção/métodos
6.
Angew Chem Int Ed Engl ; 59(32): 13295-13304, 2020 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-32337801

RESUMO

The F1 FO -ATP synthase is required for growth and viability of Mycobacterium tuberculosis and is a validated clinical target. A mycobacterium-specific loop of the enzyme's rotary γ subunit plays a role in the coupling of ATP synthesis within the enzyme complex. We report the discovery of a novel antimycobacterial, termed GaMF1, that targets this γ subunit loop. Biochemical and NMR studies show that GaMF1 inhibits ATP synthase activity by binding to the loop. GaMF1 is bactericidal and is active against multidrug- as well as bedaquiline-resistant strains. Chemistry efforts on the scaffold revealed a dynamic structure activity relationship and delivered analogues with nanomolar potencies. Combining GaMF1 with bedaquiline or novel diarylquinoline analogues showed potentiation without inducing genotoxicity or phenotypic changes in a human embryonic stem cell reporter assay. These results suggest that GaMF1 presents an attractive lead for the discovery of a novel class of anti-tuberculosis F-ATP synthase inhibitors.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , ATPases Bacterianas Próton-Translocadoras/antagonistas & inibidores , Diarilquinolinas/farmacologia , Inibidores Enzimáticos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Benzamidas/química , Benzamidas/farmacologia , Benzamidas/toxicidade , Sinergismo Farmacológico , Células-Tronco Embrionárias/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/toxicidade , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/enzimologia , Pirimidinas/química , Pirimidinas/farmacologia , Pirimidinas/toxicidade , Relação Estrutura-Atividade
7.
Acta Crystallogr D Struct Biol ; 76(Pt 4): 332-339, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32254057

RESUMO

Confidence maps provide complementary information for interpreting cryo-EM densities as they indicate statistical significance with respect to background noise. They can be thresholded by specifying the expected false-discovery rate (FDR), and the displayed volume shows the parts of the map that have the corresponding level of significance. Here, the basic statistical concepts of confidence maps are reviewed and practical guidance is provided for their interpretation and usage inside the CCP-EM suite. Limitations of the approach are discussed and extensions towards other error criteria such as the family-wise error rate are presented. The observed map features can be rendered at a common isosurface threshold, which is particularly beneficial for the interpretation of weak and noisy densities. In the current article, a practical guide is provided to the recommended usage of confidence maps.


Assuntos
Microscopia Crioeletrônica/métodos , ATPases Bacterianas Próton-Translocadoras/química , Gráficos por Computador , Modelos Moleculares , Conformação Proteica , Ribossomos/química , Eletricidade Estática , Estatística como Assunto , Vírus do Mosaico do Tabaco , Interface Usuário-Computador
8.
Nat Commun ; 11(1): 1478, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198374

RESUMO

The Escherichia coli transcription-repair coupling factor Mfd displaces stalled RNA polymerase and delivers the stall site to the nucleotide excision repair factors UvrAB for damage detection. Whether this handoff from RNA polymerase to UvrA occurs via the Mfd-UvrA2-UvrB complex or alternate reaction intermediates in cells remains unclear. Here, we visualise Mfd in actively growing cells and determine the catalytic requirements for faithful recruitment of nucleotide excision repair proteins. We find that ATP hydrolysis by UvrA governs formation and disassembly of the Mfd-UvrA2 complex. Further, Mfd-UvrA2-UvrB complexes formed by UvrB mutants deficient in DNA loading and damage recognition are impaired in successful handoff. Our single-molecule dissection of interactions of Mfd with its partner proteins inside live cells shows that the dissociation of Mfd is tightly coupled to successful loading of UvrB, providing a mechanism via which loading of UvrB occurs in a strand-specific manner.


Assuntos
Enzimas Reparadoras do DNA/metabolismo , Reparo do DNA/fisiologia , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Imagem Individual de Molécula/métodos , Fatores de Transcrição/metabolismo , Adenosina Trifosfatases , Proteínas de Bactérias , ATPases Bacterianas Próton-Translocadoras , DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas de Ligação a DNA , RNA Polimerases Dirigidas por DNA/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Modelos Moleculares , Complexos Multienzimáticos/metabolismo , Conformação Proteica , Dedos de Zinco/genética , Dedos de Zinco/fisiologia
9.
Biochimie ; 165: 156-160, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31377193

RESUMO

Mycobacterium tuberculosis (Mtb) protein tyrosine phosphatase (PtpA) has so far been known to control intracellular survival of mycobacteria; whereas the ATP synthase which is essential for mycobacterial growth has recently been contemplated in developing a breakthrough anti-TB drug, diarylquinoline. Since both of these enzymes have been established as validated drug targets; we report a robust and functional relationship between these two enzymes through a series of experiments using Mtb H37Ra. In the present study we report that the mycobacterial ATP synthase alpha subunit is regulated by PtpA. We generated gene knock-out for the enzyme PtpA and subjected to determine the mycobacterial replication and the proteome profile of wild type, mutant (ΔptpA) and complemented (ΔptpA:ptpA) strains of Mtb H37Ra. A substantial amount of decrease in the protein level of ATP synthase alpha subunit (AtpA) in case of mutant H37Ra was observed, while the levels of the enzyme were either increased or remained unchanged, in wild type and in the complemented strains.


Assuntos
Proteínas de Bactérias/fisiologia , ATPases Bacterianas Próton-Translocadoras/metabolismo , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Proteínas Tirosina Fosfatases/fisiologia , Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Diarilquinolinas/farmacologia , Técnicas de Inativação de Genes , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Proteínas Tirosina Fosfatases/genética
10.
Artigo em Inglês | MEDLINE | ID: mdl-31138569

RESUMO

Bedaquiline resistance within Mycobacterium tuberculosis may arise through efflux-based (rv0678) or target-based (atpE) pathway mutations. M. tuberculosis mutant populations from each of five sequential steps in a passaging approach, using a pyrazinamide-resistant ATCC strain, were subjected to MIC determinations and whole-genome sequencing. Exposure to increasing bedaquiline concentrations resulted in increasing phenotypic resistance (up to >2 µg/ml) through MIC determination on solid medium (Middlebrook 7H10). rv0678 mutations were dynamic, while atpE mutations were fixed, once occurring. We present the following hypothesis for in vitro emergence of bedaquiline resistance: rv0678 mutations may be the first transient step in low-level resistance acquisition, followed by high-level resistance due to fixed atpE mutations.


Assuntos
Proteínas de Bactérias/genética , Diarilquinolinas/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Mutação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Antituberculosos/farmacologia , ATPases Bacterianas Próton-Translocadoras/genética , Farmacorresistência Bacteriana/genética , Testes de Sensibilidade Microbiana
11.
Mar Drugs ; 17(2)2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30759807

RESUMO

The cyclic peptides portoamides produced by the cyanobacterium Phormidium sp. LEGE 05292 were previously isolated and their ability to condition microcommunities by allelopathic effect was described. These interesting bioactive properties are, however, still underexplored as their biotechnological applications may be vast. This study aims to investigate the antifouling potential of portoamides, given that a challenge in the search for new environmentally friendly antifouling products is to find non-toxic natural alternatives with the ability to prevent colonization of different biofouling species, from bacteria to macroinvertebrates. A multi-bioassay approach was applied to assess portoamides antifouling properties, marine ecotoxicity and molecular mode of action. Results showed high effectiveness in the prevention of mussel larvae settlement (EC50 = 3.16 µM), and also bioactivity towards growth and biofilm disruption of marine biofouling bacterial strains, while not showing toxicity towards both target and non-target species. Antifouling molecular targets in mussel larvae include energy metabolism modifications (failure in proton-transporting ATPases activity), structural alterations of the gills and protein and gene regulatory mechanisms. Overall, portoamides reveal a broad-spectrum bioactivity towards diverse biofouling species, including a non-toxic and reversible effect towards mussel larvae, showing potential to be incorporated as an active ingredient in antifouling coatings.


Assuntos
Amidas/farmacologia , Biofilmes/efeitos dos fármacos , Incrustação Biológica/prevenção & controle , Produtos Biológicos/farmacologia , Cianobactérias/metabolismo , Animais , Antibacterianos/farmacologia , Artemia , ATPases Bacterianas Próton-Translocadoras/antagonistas & inibidores , Bioensaio/métodos , Cianobactérias/química , Relação Dose-Resposta a Droga , Metabolismo Energético/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Brânquias/efeitos dos fármacos , Larva , Microalgas/efeitos dos fármacos , Mytilus , Percepção de Quorum/efeitos dos fármacos
12.
Microbiologyopen ; 8(2): e00633, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29682906

RESUMO

This study aimed to evaluate the profiles of Streptococcus thermophilus nutrient requirements to guide the design of media for high cell density culturing. The growth kinetics, physiological state, and nutrient requirement profiles of S. thermophilus were analyzed in chemically defined media. The results showed that the intracellular ATP concentration, H+ -ATPase activity, NADH/NAD+ , and NH3 concentrations varied with intracellular pH. The nutrient components with the highest amounts required were Leu and Asp; ascorbic acid and p-amino benzoic acid; K+ and PO43- ; and guanine and uracil. The nutrient components with the largest required ratios were Arg, His, and Met; folic acid, cyanocobalamine, biotin, and nicotinic acid; Ca2+ and Mg2+ ; and guanine and uracil. In this study, different nutrient components were primarily used at different phase. Trp, Tyr, calcium pantothenate, thiamine, guanine, and Mg2+ were mainly used from late-lag to midexponential phase. Met, Pro, Phe, Ala, Gly, nicotinic acid, and riboflavin were mainly used from midexponential to late-exponential phase. The highest bioavailabilities of nutrient components were also found at diverse phase. Met, Leu, Ile, Asn, Glu, Lys, Pro, Gly, riboflavin, nicotinic acid, adenine, uracil, inosine, and Ca2+ had the highest bioavailability from late-lag to midexponential phase. Lactose, Glu, Asp, His, Trp, Cys, Val, Arg, Phe, Ala, Ser, Thr, Tyr, folate and cobalamin, calcium pantothenate, ascorbic acid, thiamine, biotin, p-amino benzoic acid, vitamin B6 , K+ , Mg2+ , guanine, xanthine, and PO43- had the highest bioavailability from midexponential to late-exponential phase. This study elucidated the nutrient requirement profiles with culture time and biomass at various average growth rates during the growth of S. thermophilus. The present results will help to formulate complex media for high cell density cultivation and provide the theoretical basis for S. thermophilus feeding strategies.


Assuntos
Nutrientes/metabolismo , Streptococcus thermophilus/crescimento & desenvolvimento , Streptococcus thermophilus/metabolismo , Trifosfato de Adenosina/análise , Amônia/análise , ATPases Bacterianas Próton-Translocadoras/análise , Meios de Cultura/química , Fermentação , Concentração de Íons de Hidrogênio , NAD/análise , Streptococcus thermophilus/química
13.
J Food Sci ; 84(1): 138-146, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30569590

RESUMO

Many novel bacterial targets and natural inhibitors of enzymes are currently being considered to overcome antibiotic resistance of Escherichia coli. Hence, in this study, 20 essential oil constituents were screened for their potential inhibitory effect on E. coli ATP synthase. This enzyme is involved in the hydrolysis of ATP into ADP and inorganic phosphate (Pi). First, E. coli membrane ATP synthase was isolated via cell lysis. A spectrophotometric method was optimized to quantify the released phosphate from ATP hydrolysis in order to follow the enzymatic activity. The method was validated by determining the kinetic parameters of this reaction (Km = 144.66 µM and Vmax = 270.27 µM/min), and through the inhibition assays of ATP synthase using three reference inhibitors, thymoquinone (half maximal inhibitory concentration [IC50 ] = 50.93 µM), resveratrol (maximum inhibition of 40%), and quercetin (IC50 = 29.01 µM). Among the studied essential oil components, α-terpinene was the most potent inhibitor (IC50 = 19.74 µM) followed by ß-pinene, isoeugenol, eugenol, and estragole.


Assuntos
ATPases Bacterianas Próton-Translocadoras/antagonistas & inibidores , Escherichia coli/efeitos dos fármacos , Óleos Voláteis/análise , Trifosfato de Adenosina/metabolismo , ATPases Bacterianas Próton-Translocadoras/metabolismo , Escherichia coli/enzimologia , Concentração de Íons de Hidrogênio , Hidrólise , Concentração Inibidora 50 , Fosfatos/análise
14.
Cell ; 175(2): 571-582.e11, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30146159

RESUMO

Elucidating the benefits of individual microbiota-derived molecules in host animals is important for understanding the symbiosis between humans and their microbiota. The bacteria-secreted enterobactin (Ent) is an iron scavenging siderophore with presumed negative effects on hosts. However, the high prevalence of Ent-producing commensal bacteria in the human gut raises the intriguing question regarding a potential host mechanism to beneficially use Ent. We discovered an unexpected and striking role of Ent in supporting growth and the labile iron pool in C. elegans. We show that Ent promotes mitochondrial iron uptake and does so, surprisingly, by binding to the ATP synthase α subunit, which acts inside of mitochondria and independently of ATP synthase. We also demonstrated the conservation of this mechanism in mammalian cells. This study reveals a distinct paradigm for the "iron tug of war" between commensal bacteria and their hosts and an important mechanism for mitochondrial iron uptake and homeostasis.


Assuntos
Enterobactina/fisiologia , Ferro/metabolismo , Sideróforos/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , ATPases Bacterianas Próton-Translocadoras/metabolismo , ATPases Bacterianas Próton-Translocadoras/fisiologia , Transporte Biológico , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Enterobactina/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/fisiologia , Células HEK293 , Humanos , Ferro/fisiologia , Mitocôndrias/metabolismo
15.
Artigo em Inglês | MEDLINE | ID: mdl-29712658

RESUMO

Chemotherapeutic options against Mycobacterium abscessus infections are very limited. Bedaquiline, a new antituberculosis (anti-TB) drug, is effective for the treatment of multidrug-resistant TB. However, few data are available on bedaquiline for treatment of M. abscessus infections. In this study, we determined the profile for in vitro susceptibility of M. abscessus clinical isolates to bedaquiline and investigated the potential molecular mechanisms of decreased susceptibility. A total of 197 M. abscessus clinical isolates were collected from sputum and bronchoalveolar fluid of patients with lung infections. Standard broth microdilution test revealed that bedaquiline exhibited high in vitro killing activity against M. abscessus isolates, with a MIC50 of 0.062 and a MIC90 of 0.125 mg/liter. Whole-genome sequencing data showed that no nonsynonymous mutation occurred in atpE, the gene encoding the bedaquiline-targeted protein. However, of 6 strains with decreased susceptibility of bedaquiline (MIC = 0.5 to 1 mg/liter), 3 strains had nonsynonymous mutations in mab_4384, the gene encoding the repressor of efflux pump MmpS5/MmpL5. Quantitative reverse transcription-PCR (qRT-PCR) analysis showed that the expression of MmpS5/MmpL5 in the group with decreased susceptibility to bedaquiline was significantly higher than in those with medium MICs (MIC = 0.125 to 0.5 mg/liter) or in the low-MIC group (MIC ≤ 0.062 mg/liter). Two isolates with increased MICs did not show overexpression of MmpS5/MmpL5, which could not be explained by known molecular mechanisms. This is the first report showing the association of MmpS5/MmpL5 with decreased bedaquiline susceptibility in M. abscessus clinical isolates and suggesting the presence of other, yet-to-be identified mechanisms for decreased bedaquiline susceptibility in M. abscessus.


Assuntos
Antituberculosos/farmacologia , Diarilquinolinas/farmacologia , Farmacorresistência Bacteriana/genética , Mycobacterium abscessus/efeitos dos fármacos , Mycobacterium abscessus/isolamento & purificação , ATPases Bacterianas Próton-Translocadoras/genética , Genoma Bacteriano/genética , Humanos , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Mycobacterium abscessus/genética , Sequenciamento Completo do Genoma
16.
Tuberculosis (Edinb) ; 108: 56-63, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29523328

RESUMO

A limited number of anti-tuberculosis drug candidates with novel mode of action have entered clinical trials in recent years. ATP synthase is one such validated drug target which has yielded a drug recently. The aim of this study was to identify the novel chemical scaffolds targeting the Mycobacterium tuberculosis (M. tuberculosis) ATP synthase. In this study, inverted membrane vesicles of Mycobacterium smegmatis were prepared to establish luciferin based ATP estimation assay. This assay was used to screen 700 compounds which were earlier found to be active on the whole cell of M. tuberculosis. Antibacterial activity of hits against various susceptible and drug-resistant strains of M. tuberculosis was evaluated using the microplate alamar blue assay and their cytotoxicity was also determined to select the safe compounds for further study. Screening of 700 compounds resulted in the identification of two compounds (5228485 and 5220632) exhibiting an IC50 of 0.32 and 4.0 µg/ml respectively. Both compounds showed excellent anti-TB activity (MIC of 0.5-2.0 µg/ml against Mtb H37Rv) and low cytotoxicity in human cell line and sub-mitochondrial particles. The three-dimensional structure of M. tuberculosis ATPase was predicted using in-silico approach and docking studies were performed with the active compounds. The interaction between compounds and bacterial ATP synthase was confirmed by molecular docking analysis. In conclusion screening of compound library has resulted in the identification of two novel chemical scaffolds targeting mycobacterial ATP synthase.


Assuntos
Antituberculosos/farmacologia , ATPases Bacterianas Próton-Translocadoras/antagonistas & inibidores , Metabolismo Energético/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Simulação de Acoplamento Molecular , Mycobacterium smegmatis/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas , Trifosfato de Adenosina/biossíntese , Animais , Antituberculosos/química , Antituberculosos/metabolismo , ATPases Bacterianas Próton-Translocadoras/metabolismo , Sítios de Ligação , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Células Hep G2 , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Mycobacterium smegmatis/enzimologia , Mycobacterium tuberculosis/enzimologia , Ligação Proteica , Conformação Proteica , Fatores de Tempo
17.
Microb Ecol ; 75(4): 834-846, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29063147

RESUMO

Biogeographical studies considering the entire bacterial community may underestimate mechanisms of bacterial assemblages at lower taxonomic levels. In this context, the study aimed to identify factors affecting the spatial and temporal dynamic of the Mycobacterium, a genus widespread in aquatic ecosystems. Nontuberculous mycobacteria (NTM) density variations were quantified in the water column of freshwater lakes at the regional scale (annual monitoring of 49 lakes in the Paris area) and at the local scale (2-year monthly monitoring in Créteil Lake) by real-time quantitative PCR targeting the atpE gene. At the regional scale, mycobacteria densities in water samples ranged from 6.7 × 103 to 1.9 × 108 genome units per liter. Density variations were primarily explained by water pH, labile iron, and dispersal processes through the connection of the lakes to a river. In Créteil Lake, no spatial variation of mycobacterial densities was noticed over the 2-year monthly survey, except after large rainfall events. Indeed, storm sewer effluents locally and temporarily increased NTM densities in the water column. The temporal dynamic of the NTM densities in Créteil Lake was associated with suspended solid concentrations. No clear seasonal variation was noticed despite a shift in NTM densities observed over the 2012-2013 winter. Temporal NTM densities fluctuations were well predicted by the neutral community model, suggesting a random balance between loss and gain of mycobacterial taxa within Créteil Lake. This study highlights the importance of considering multiple spatial scales for understanding the spatio-temporal dynamic of bacterial populations in natural environments.


Assuntos
Biodiversidade , Ecossistema , Lagos/microbiologia , Mycobacterium , Microbiologia da Água , Carga Bacteriana , ATPases Bacterianas Próton-Translocadoras/genética , DNA Bacteriano/genética , Monitoramento Ambiental , Sedimentos Geológicos/microbiologia , Lagos/química , Mycobacterium/classificação , Mycobacterium/genética , Micobactérias não Tuberculosas/classificação , Micobactérias não Tuberculosas/genética , Paris , Reação em Cadeia da Polimerase em Tempo Real , Rios/microbiologia , Estações do Ano
18.
Proc Natl Acad Sci U S A ; 114(43): 11291-11296, 2017 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-29073046

RESUMO

ATP synthase is a rotating membrane protein that synthesizes ATP through proton-pumping activity across the membrane. To unveil the mechanical impact of this molecular active pump on the bending properties of its lipid environment, we have functionally reconstituted the ATP synthase in giant unilamellar vesicles and tracked the membrane fluctuations by means of flickering spectroscopy. We find that ATP synthase rotates at a frequency of about 20 Hz, promoting large nonequilibrium deformations at discrete hot spots in lipid vesicles and thus inducing an overall membrane softening. The enhanced nonequilibrium fluctuations are compatible with an accumulation of active proteins at highly curved membrane sites through a curvature-protein coupling mechanism that supports the emergence of collective effects of rotating ATP synthases in lipid membranes.


Assuntos
ATPases Bacterianas Próton-Translocadoras/metabolismo , Membrana Celular/química , Membrana Celular/metabolismo , Proteínas de Escherichia coli/metabolismo , Trifosfato de Adenosina/biossíntese , ATPases Bacterianas Próton-Translocadoras/química , ATPases Bacterianas Próton-Translocadoras/genética , Membrana Celular/efeitos dos fármacos , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Corantes Fluorescentes/química , Concentração de Íons de Hidrogênio , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Microscopia de Vídeo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Rodamina 123/química , Lipossomas Unilamelares/química , Lipossomas Unilamelares/metabolismo , Valinomicina/farmacologia
19.
Artigo em Inglês | MEDLINE | ID: mdl-28807917

RESUMO

Pulmonary infections caused by Mycobacterium abscessus are emerging as a global threat, especially in cystic fibrosis patients. Further intensifying the concern of M. abscessus infection is the recent evidence of human-to-human transmission of the infection. M. abscessus is a naturally multidrug-resistant fast-growing pathogen for which pharmacological options are limited. Repurposing antitubercular drugs represents an attractive option for the development of chemotherapeutic alternatives against M. abscessus infections. Bedaquiline (BDQ), an ATP synthase inhibitor, has recently been approved for the treatment of multidrug-resistant tuberculosis. Herein, we show that BDQ has a very low MIC against a vast panel of clinical isolates. Despite being bacteriostatic in vitro, BDQ was highly efficacious in a zebrafish model of M. abscessus infection. Remarkably, a very short period of treatment was sufficient to protect the infected larvae from M. abscessus-induced killing. This was corroborated with reduced numbers of abscesses and cords, considered to be major pathophysiological signs in infected zebrafish. Mode-of-action studies revealed that BDQ triggered a rapid depletion of ATP in M. abscessusin vitro, consistent with the drug targeting the FoF1 ATP synthase. Importantly, despite a failure to select in vitro for spontaneous mutants that are highly resistant to BDQ, the transfer of single nucleotide polymorphisms leading to D29V or A64P substitutions in atpE conferred high resistance, thus resolving the target of BDQ in M. abscessus Overall, this study indicates that BDQ is active against M. abscessusin vitro and in vivo and should be considered for clinical use against the difficult-to-manage M. abscessus pulmonary infections.


Assuntos
Antituberculosos/farmacologia , ATPases Bacterianas Próton-Translocadoras/antagonistas & inibidores , Diarilquinolinas/farmacologia , Mycobacterium abscessus/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Animais , ATPases Bacterianas Próton-Translocadoras/genética , ATPases Bacterianas Próton-Translocadoras/metabolismo , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Infecções por Mycobacterium não Tuberculosas/microbiologia , Mycobacterium abscessus/metabolismo , Polimorfismo de Nucleotídeo Único , Peixe-Zebra/microbiologia
20.
Antonie Van Leeuwenhoek ; 110(11): 1475-1483, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28647822

RESUMO

An aerobic, Gram-stain negative, short rod-shaped and motile strain, 36-5-1T, was isolated from the roots of Nitraria sibirica in Zhangye city, Gansu province, north-west of China. Phylogenetic analysis based on the 16S rRNA gene sequence and two housekeeping genes (glnA and atpD) indicated that the strain represents a novel species closely related to the Devosia, Rhizobium and Devosia genera with 98.3, 96.2 and 91.1% similarities, respectively. The strain 36-5-1T contained Q-10 as the predominant ubiquinone and 16:0 (36.8%) as the major fatty acid; a large amount of unidentified glycolipid, diphosphatidylglycerol, phosphatidylglycerol and a small amount of unidentified polar lipids were present as polar lipids. In addition, the G+C content of the genomic DNA was 61.7 mol% and the DNA-DNA hybridization with type strains Devosia geojensis BD-c194T and Devosia pacifica NH131T 44.1 ± 1.1 and 40.2 ± 1.7, respectively. Based on chemotaxonomic data and molecular properties, strain 36-5-1T represents a novel species within the genus Devosia, for which the name Devosia nitraria sp. nov. is proposed. The type strain is 36-5-1T (=CGMCC1.15704T=NBRC112416T).


Assuntos
Hyphomicrobiaceae/classificação , Filogenia , ATPases Bacterianas Próton-Translocadoras/genética , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/análise , Glutamato-Amônia Ligase/genética , Glicolipídeos/análise , Hyphomicrobiaceae/química , Hyphomicrobiaceae/genética , Fosfolipídeos/análise , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Microbiologia do Solo
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