P2X receptors (P2X1-7) are trimeric ion channels activated by extracellular ATP. Each P2X subunit contains two transmembrane helices (TM1 and TM2). We substituted all residues in TM1 of rat P2X7 with alanine or leucine one by one, expressed mutants in HEK293T cells, and examined the pore permeability by recording both membrane currents and fluorescent dye uptake in response to agonist application. Alanine substitution of G27, K30, H34, Y40, F43, L45, M46, and D48 inhibited agonist-stimulated membrane current and dye uptake, and all but one substitution, D48A, prevented surface expression. Mutation V41A partially reduced both membrane current and dye uptake, while W31A and A44L showed reduced dye uptake not accompanied by reduced membrane current. Mutations T28A, I29A, and L33A showed small changes in agonist sensitivity, but they had no or small impact on dye uptake function. Replacing charged residues with residues of the same charge (K30R, H34K, and D48E) rescued receptor function, while replacement with residues of opposite charge inhibited (K30E and H34E) or potentiated (D48K) receptor function. Prolonged stimulation with agonist-induced current facilitation and a leftward shift in the dose-response curve in the P2X7 wild-type and most functional mutants, but sensitization was absent in the W31A, L33A, and A44L. Detailed analysis of the decay of responses revealed two kinetically distinct mechanisms of P2X7 deactivation: fast represents agonist unbinding, and slow might represent resetting of the receptor to the resting closed state. These results indicate that conserved and receptor-specific TM1 residues control surface expression of the P2X7 protein, non-polar residues control receptor sensitization, and D48 regulates intrinsic channel properties.

• MeSH
• adenosintrifosfát farmakologie   metabolismus   MeSH
• biologický transport MeSH
• HEK293 buňky MeSH
• iontové kanály * metabolismus   MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• mutace genetika   MeSH
• proteinové domény MeSH
• purinergní receptory P2X7 * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Although paclitaxel (PTX) is potent chemotherapeutic agent commonly used in variety of cancers, in colorectal carcinoma its usage is excluded because of low effectivity. Up to now, some experimental attempts were utilized to improve sensitivity of colorectal carcinoma to PTX. We used a slow sulfide donor GYY4137 to increase sensitivity of colorectal carcinoma cells to PTX. As a model of colorectal carcinoma, we utilized three different cell lines - HCT116, SW620 and DLD1. We compared IC50 for PTX and PTX/GYY4137, cell cycle, apoptosis, ATP levels and changes in intracellular pH. We observed significant decrease in IC50 levels in PTX/GYY4137 groups compared to PTX in all three cell lines. PTX arrested cell cycle in G2/M phase. Differences in S phase were observed in HCT116 and DLD1 cells treated with 20 nM PTX/GYY4137, but not in SW620 cell. GYY4137 increased early, but not late phase of apoptosis. This increase was not detected in non-cancer EAHy926 cells. Upregulation of IP3R1 suggested involvement of these receptors in PTX and/or GYY4137 induced apoptosis. We also observed partial ATP depletion and intracellular acidification in PTX treated groups. In PTX/GYY4137 groups of all three cell lines no ATP depletion was detectable and intracellular acidification was lower than in PTX treated groups. Slight differences in all measured parameters were determined among HCT116, SW620 and DLD1 cells, which is probably due to physiological variations in these cells. Taking together, sensitivity of PTX to colorectal carcinoma cell lines could be increased by slow sulfide donor GYY4137, probably through potentiation of apoptosis.

• MeSH
• adenosintrifosfát farmakologie   MeSH
• apoptóza MeSH
• kolorektální nádory * patologie   MeSH
• lidé MeSH
• morfoliny MeSH
• nádorové buněčné linie MeSH
• organothiofosforové sloučeniny MeSH
• paclitaxel farmakologie   MeSH
• sulfan * metabolismus   MeSH
• sulfidy farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The RAD51 recombinase assembles as helical nucleoprotein filaments on single-stranded DNA (ssDNA) and mediates invasion and strand exchange with homologous duplex DNA (dsDNA) during homologous recombination (HR), as well as protection and restart of stalled replication forks. Strand invasion by RAD51-ssDNA complexes depends on ATP binding. However, RAD51 can bind ssDNA in non-productive ADP-bound or nucleotide-free states, and ATP-RAD51-ssDNA complexes hydrolyse ATP over time. Here, we define unappreciated mechanisms by which the RAD51 paralog complex RFS-1/RIP-1 limits the accumulation of RAD-51-ssDNA complexes with unfavorable nucleotide content. We find RAD51 paralogs promote the turnover of ADP-bound RAD-51 from ssDNA, in striking contrast to their ability to stabilize productive ATP-bound RAD-51 nucleoprotein filaments. In addition, RFS-1/RIP-1 inhibits binding of nucleotide-free RAD-51 to ssDNA. We propose that 'nucleotide proofreading' activities of RAD51 paralogs co-operate to ensure the enrichment of active, ATP-bound RAD-51 filaments on ssDNA to promote HR.

• MeSH
• adenosindifosfát farmakologie   MeSH
• adenosintrifosfát farmakologie   MeSH
• Caenorhabditis elegans metabolismus   MeSH
• druhová specificita MeSH
• fluorescence MeSH
• interferometrie MeSH
• jednovláknová DNA metabolismus   MeSH
• nukleotidy metabolismus   MeSH
• proteiny Caenorhabditis elegans metabolismus   MeSH
• rekombinasa Rad51 chemie   metabolismus   MeSH
• sekvenční homologie aminokyselin * MeSH
• stabilita proteinů účinky léků   MeSH
• vazba proteinů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tuberculosis (TB) remains one of the major health concerns worldwide. Mycobacterium tuberculosis (Mtb), the causative agent of TB, can flexibly change its metabolic processes during different life stages. Regulation of key metabolic enzyme activities by intracellular conditions, allosteric inhibition or feedback control can effectively contribute to Mtb survival under different conditions. Phosphofructokinase (Pfk) is one of the key enzymes regulating glycolysis. Mtb encodes two Pfk isoenzymes, Pfk A/Rv3010c and Pfk B/Rv2029c, which are differently expressed upon transition to the hypoxia-induced non-replicating state of the bacteria. While pfkB gene and protein expression are upregulated under hypoxic conditions, Pfk A levels decrease. Here, we present biochemical characterization of both Pfk isoenzymes, revealing that Pfk A and Pfk B display different kinetic properties. Although the glycolytic activity of Pfk A is higher than that of Pfk B, it is markedly inhibited by an excess of both substrates (fructose-6-phosphate and ATP), reaction products (fructose-1,6-bisphosphate and ADP) and common metabolic allosteric regulators. In contrast, synthesis of fructose-1,6-bisphosphatase catalyzed by Pfk B is not regulated by higher levels of substrates, and metabolites. Importantly, we found that only Pfk B can catalyze the reverse gluconeogenic reaction. Pfk B thus can support glycolysis under conditions inhibiting Pfk A function.

• MeSH
• adenosindifosfát metabolismus   farmakologie   MeSH
• adenosintrifosfát metabolismus   farmakologie   MeSH
• alosterická regulace MeSH
• bakteriální proteiny antagonisté a inhibitory   metabolismus   MeSH
• enzymová indukce MeSH
• fosfofruktokinasy antagonisté a inhibitory   metabolismus   MeSH
• fruktosadifosfáty biosyntéza   farmakologie   MeSH
• fruktosafosfáty metabolismus   farmakologie   MeSH
• glukoneogeneze MeSH
• glykolýza MeSH
• hexosafosfáty metabolismus   MeSH
• izoenzymy antagonisté a inhibitory   metabolismus   MeSH
• katalýza MeSH
• kinetika MeSH
• kyslík farmakologie   MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• Mycobacterium tuberculosis účinky léků   enzymologie   MeSH
• pyruvátkinasa metabolismus   MeSH
• rekombinantní proteiny metabolismus   MeSH
• substrátová specifita MeSH
• zpětná vazba fyziologická MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

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.

• MeSH
• adenosintrifosfát chemická syntéza   chemie   farmakologie   MeSH
• antibakteriální látky chemická syntéza   chemie   farmakologie   MeSH
• DNA gyráza metabolismus   MeSH
• DNA-topoisomerasa IV antagonisté a inhibitory   metabolismus   MeSH
• Escherichia coli účinky léků   enzymologie   patogenita   MeSH
• krystalografie rentgenová MeSH
• mikrobiální testy citlivosti MeSH
• molekulární struktura MeSH
• simulace molekulového dockingu MeSH
• Staphylococcus aureus účinky léků   enzymologie   patogenita   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH

Remdesivir was shown to inhibit RNA-dependent RNA-polymerases (RdRp) from distinct viral families such as from Filoviridae (Ebola) and Coronaviridae (SARS-CoV, SARS-CoV-2, MERS). In this study, we tested the ability of remdesivir to inhibit RdRps from the Flaviviridae family. Instead of remdesivir, we used the active species that is produced in cells from remdesivir, the appropriate triphosphate, which could be directly tested in vitro using recombinant flaviviral polymerases. Our results show that remdesivir can efficiently inhibit RdRps from viruses causing severe illnesses such as Yellow fever, West Nile fever, Japanese and Tick-borne encephalitis, Zika and Dengue. Taken together, this study demonstrates that remdesivir or its derivatives have the potential to become a broad-spectrum antiviral agent effective against many RNA viruses.

• MeSH
• adenosintrifosfát analogy a deriváty   chemie   farmakologie   MeSH
• antivirové látky chemie   farmakologie   MeSH
• Betacoronavirus účinky léků   enzymologie   MeSH
• COVID-19 MeSH
• Flavivirus účinky léků   enzymologie   MeSH
• inhibiční koncentrace 50 MeSH
• koronavirové infekce farmakoterapie   virologie   MeSH
• lidé MeSH
• pandemie MeSH
• RNA-dependentní RNA-polymerasa antagonisté a inhibitory   metabolismus   MeSH
• RNA-viry účinky léků   enzymologie   MeSH
• SARS-CoV-2 MeSH
• virová pneumonie farmakoterapie   virologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chromatin remodelers are complexes able to both alter histone-DNA interactions and to mobilize nucleosomes. The mechanism of their action and the conformation of remodeled nucleosomes remain a matter of debates. In this work we compared the type and structure of the products of nucleosome remodeling by SWI/SNF and ACF complexes using high-resolution microscopy combined with novel biochemical approaches. We find that SWI/SNF generates a multitude of nucleosome-like metastable particles termed "remosomes". Restriction enzyme accessibility assay, DNase I footprinting and AFM experiments reveal perturbed histone-DNA interactions within these particles. Electron cryo-microscopy shows that remosomes adopt a variety of different structures with variable irregular DNA path, similar to those described upon RSC remodeling. Remosome DNA accessibility to restriction enzymes is also markedly increased. We suggest that the generation of remosomes is a common feature of the SWI/SNF family remodelers. In contrast, the ACF remodeler, belonging to ISWI family, only produces repositioned nucleosomes and no evidence for particles associated with extra DNA, or perturbed DNA paths was found. The remosome generation by the SWI/SNF type of remodelers may represent a novel mechanism involved in processes where nucleosomal DNA accessibility is required, such as DNA repair or transcription regulation.

• MeSH
• adenosintrifosfát metabolismus   farmakologie   MeSH
• bezbuněčný systém MeSH
• chromozomální proteiny, nehistonové fyziologie   MeSH
• DNA bakterií metabolismus   MeSH
• DNA footprinting MeSH
• fungální proteiny fyziologie   MeSH
• histony genetika   metabolismus   MeSH
• mikroskopie atomárních sil MeSH
• multiproteinové komplexy fyziologie   MeSH
• nukleozomy fyziologie   ultrastruktura   MeSH
• plazmidy chemie   MeSH
• proteiny vázající RNA fyziologie   MeSH
• rekombinantní proteiny metabolismus   MeSH
• restrikční endonukleasy typu II MeSH
• restrukturace chromatinu genetika   fyziologie   MeSH
• Saccharomyces cerevisiae metabolismus   ultrastruktura   MeSH
• Xenopus laevis genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

After discovery of antiphospholipid syndrome (APS) our understanding of molecular mechanisms of living matter has become more sophisticated and on this way monocytes has become crucial player, particularly in pathogenesis of APS. Thrombotic and non-thrombotic complications of APS could be explained by monocytes' activation too. But mechanisms underlying their activation are poorly investigated. So we aimed to determine transcriptional activity of monocytes after exposing them to low concentrations of lipopolysaccharide (LPS) and LPS+ATP using comparative of RT-PCR. Our study included eleven women suffering from recurrent miscarriages and APS (mean age 30±5,6 years). Nine healthy women (mean age of 29±8,5 years) without a positive family history of APS, autoimmune diseases and thrombosis were chosen as a control group. The results showed increasing levels of TLR2, IL-23, CCL2, CXCL10, IL-1β and IL-6 in APS cells, while in healthy cells LPS resulted in IL-6 and STAT3 elevated mRNAs. Double stimulation of APS cells resulted in decreased mRNA levels of CCL-2, IL-1β, and mRNA NLRP3 in healthy cells. At the same time TLR2 mRNAs were elevated in both groups after double stimulation. Thus increased sensitivity of APS cells to LPS may contribute to thrombus formation. Low concentration of ATP diminishes LPS-induced inflammatory state of APS monocytes, which might be one of potential regulatory mechanisms.

• MeSH
• adenosintrifosfát farmakologie   MeSH
• antifosfolipidový syndrom imunologie   metabolismus   patologie   MeSH
• chemokiny krev   genetika   MeSH
• dospělí MeSH
• exprese genu MeSH
• habituální potrat imunologie   MeSH
• interleukiny krev   genetika   MeSH
• lidé MeSH
• lipopolysacharidy farmakologie   MeSH
• messenger RNA metabolismus   MeSH
• mladý dospělý MeSH
• monocyty účinky léků   imunologie   metabolismus   MeSH
• protein NLRP3 krev   genetika   MeSH
• studie případů a kontrol MeSH
• techniky in vitro MeSH
• toll-like receptor 2 krev   genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Mitochondrial evolution entailed the origin of protein import machinery that allows nuclear-encoded proteins to be targeted to the organelle, as well as the origin of cleavable N-terminal targeting sequences (NTS) that allow efficient sorting and import of matrix proteins. In hydrogenosomes and mitosomes, reduced forms of mitochondria with reduced proteomes, NTS-independent targeting of matrix proteins is known. Here, we studied the cellular localization of two glycolytic enzymes in the anaerobic pathogen Trichomonas vaginalis: PPi-dependent phosphofructokinase (TvPPi-PFK), which is the main glycolytic PFK activity of the protist, and ATP-dependent PFK (TvATP-PFK), the function of which is less clear. TvPPi-PFK was detected predominantly in the cytosol, as expected, while all four TvATP-PFK paralogues were imported into T. vaginalis hydrogenosomes, although none of them possesses an NTS. The heterologous expression of TvATP-PFK in Saccharomyces cerevisiae revealed an intrinsic capability of the protein to be recognized and imported into yeast mitochondria, whereas yeast ATP-PFK resides in the cytosol. TvATP-PFK consists of only a catalytic domain, similarly to "short" bacterial enzymes, while ScATP-PFK includes an N-terminal extension, a catalytic domain, and a C-terminal regulatory domain. Expression of the catalytic domain of ScATP-PFK and short Escherichia coli ATP-PFK in T. vaginalis resulted in their partial delivery to hydrogenosomes. These results indicate that TvATP-PFK and the homologous ATP-PFKs possess internal structural targeting information that is recognized by the hydrogenosomal import machinery. From an evolutionary perspective, the predisposition of ancient ATP-PFK to be recognized and imported into hydrogenosomes might be a relict from the early phases of organelle evolution.

• MeSH
• adenosintrifosfát farmakologie   MeSH
• difosfáty metabolismus   MeSH
• ferredoxiny metabolismus   MeSH
• fosfofruktokinasy chemie   metabolismus   MeSH
• fylogeneze MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• organely účinky léků   metabolismus   MeSH
• promotorové oblasti (genetika) genetika   MeSH
• Saccharomyces cerevisiae účinky léků   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• transport proteinů účinky léků   MeSH
• Trichomonas vaginalis účinky léků   enzymologie   MeSH
• vodík metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Antiphospholipid syndrome (APS) is an acquired autoimmune disorder characterized by recurrent thrombosis and pregnancy morbidity in association with the presence of antiphospholipid antibodies. Growing evidence supports the involvement of monocytes in APS pathogenesis. Inflammatory activation of monocytes promotes thrombus formation and other APS complications. However, mechanisms underlying their activation are poorly investigated. We aimed to determine transcriptional activity of monocytes after exposing them to low concentrations of lipopolysaccharide (LPS) and LPS + adenosine triphosphate (ATP) using comparative qRT-PCR. The results showed that LPS significantly increased transcriptional levels of TLR2, IL-23, CCL2, CXCL10, IL-1β, and IL-6 in APS cells, while, in cells from healthy donors, LPS resulted in IL-6 and STAT3 elevated mRNAs. Double stimulation of the cells resulted in decreased mRNA levels of NLRP3 in monocytes isolated from healthy donors and CCL2, IL-1β in APS cells. By contrast, TLR2 mRNAs were elevated in both investigated groups after culture of the cells with LPS + ATP. Thus, the findings indicate increased sensitivity of APS cells to LPS that may contribute to thrombus formation and enhance development or progression of autoimmune processes. Low concentrations of ATP diminish LPS-induced inflammatory state of APS monocytes which might be a potential mechanism which regulates inflammatory state of the cells.

• MeSH
• adenosintrifosfát farmakologie   MeSH
• antifosfolipidový syndrom metabolismus   MeSH
• chemokin CCL2 metabolismus   MeSH
• chemokin CXCL10 MeSH
• dospělí MeSH
• genetická anticipace účinky léků   MeSH
• interleukiny metabolismus   MeSH
• lidé MeSH
• lipopolysacharidy farmakologie   MeSH
• messenger RNA metabolismus   MeSH
• monocyty účinky léků   metabolismus   MeSH
• studie případů a kontrol MeSH
• toll-like receptor 2 metabolismus   MeSH
• transkripční faktor STAT3 metabolismus   MeSH
• zánět metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH