Rhomboid proteases form one of the most widespread intramembrane protease families. They have been implicated in variety of human diseases. The currently reported rhomboid inhibitors display some selectivity, but their construction involves multistep synthesis protocols. Here, we report benzoxazin-4-ones as novel inhibitors of rhomboid proteases with a covalent, but slow reversible inhibition mechanism. Benzoxazin-4-ones can be synthesized from anthranilic acid derivatives in a one-step synthesis, making them easily accessible. We demonstrate that an alkoxy substituent at the 2-position is crucial for potency and results in low micromolar inhibitors of rhomboid proteases. Hence, we expect that these compounds will allow rapid synthesis and optimization of inhibitors of rhomboids from different organisms.
- MeSH
- Bacillus subtilis enzymologie MeSH
- benzoxaziny chemická syntéza chemie farmakologie MeSH
- chymotrypsin antagonisté a inhibitory MeSH
- DNA vazebné proteiny antagonisté a inhibitory MeSH
- endopeptidasy MeSH
- enzymatické testy MeSH
- Escherichia coli enzymologie MeSH
- inhibitory serinových proteinas chemická syntéza chemie farmakologie MeSH
- inhibitory trypsinu chemická syntéza chemie farmakologie MeSH
- membránové proteiny antagonisté a inhibitory MeSH
- molekulární struktura MeSH
- ortoaminobenzoáty chemie MeSH
- proteiny z Escherichia coli antagonisté a inhibitory MeSH
- skot MeSH
- trypsin chemie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The coexistence of lipid domains with different degrees of lipid packing in the plasma membrane of mammalian cells has been postulated, but direct evidence has so far been challenging to obtain because of the small size and short lifetime of these domains in live cells. Here, we use fluorescence spectral correlation spectroscopy in conjunction with a probe sensitive to the membrane environment to quantify spectral fluctuations associated with dynamics of membrane domains in live cells. With this method, we show that membrane domains are present in live COS-7 cells and have a lifetime lower bound of 5.90 and 14.69 ms for the ordered and disordered phases, respectively. Comparisons to simulations indicate that the underlying mechanism of these fluctuations is complex but qualitatively described by a combination of dye diffusion between membrane domains as well as the motion of domains within the membrane.
- MeSH
- benzoxaziny chemie MeSH
- buněčná membrána chemie MeSH
- Cercopithecus aethiops MeSH
- COS buňky MeSH
- fluorescenční spektrometrie MeSH
- kvartérní amoniové sloučeniny chemie MeSH
- membránové lipidy chemie MeSH
- viabilita buněk MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Rhomboids are intramembrane serine proteases with diverse physiological functions in organisms ranging from archaea to humans. Crystal structure analysis has provided a detailed understanding of the catalytic mechanism, and rhomboids have been implicated in various disease contexts. Unfortunately, the design of specific rhomboid inhibitors has lagged behind, and previously described small molecule inhibitors displayed insufficient potency and/or selectivity. Using a computer-aided approach, we focused on the discovery of novel scaffolds with reduced liabilities and the possibility for broad structural variations. Docking studies with the E. coli rhomboid GlpG indicated that 2-styryl substituted benzoxazinones might comprise novel rhomboid inhibitors. Protease in vitro assays confirmed activity of 2-styryl substituted benzoxazinones against GlpG but not against the soluble serine protease α-chymotrypsin. Furthermore, mass spectrometry analysis demonstrated covalent modification of the catalytic residue Ser201, corroborating the predicted mechanism of inhibition and the formation of an acyl enzyme intermediate. In conclusion, 2-styryl substituted benzoxazinones are a novel rhomboid inhibitor scaffold with ample opportunity for optimization.
- MeSH
- benzoxaziny chemická syntéza chemie MeSH
- chymotrypsin chemie MeSH
- DNA vazebné proteiny antagonisté a inhibitory chemie genetika MeSH
- Drosophila chemie MeSH
- endopeptidasy chemie genetika MeSH
- enzymatické testy MeSH
- Escherichia coli enzymologie MeSH
- inhibitory serinových proteinas chemická syntéza chemie MeSH
- katalytická doména MeSH
- lidé MeSH
- membránové proteiny antagonisté a inhibitory chemie genetika MeSH
- mutace MeSH
- objevování léků MeSH
- proteiny Drosophily metabolismus MeSH
- proteiny z Escherichia coli antagonisté a inhibitory chemie genetika MeSH
- serin chemie MeSH
- simulace molekulového dockingu MeSH
- skot MeSH
- styreny chemická syntéza chemie MeSH
- transformující růstový faktor alfa metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Efavirenz is an antiretroviral drug used in the treatment of HIV-positive patients. A simple, fast and sensitive high-performance liquid chromatography (HPLC) method was developed in order to determine efavirenz in three types of samples provided from pharmacokinetic studies. The analysis took 5min and was performed using a C18 analytical column (Discovery HS C18, 150×4.6mm, particle size of 5μm) in isocratic mode with a mobile phase containing acetonitrile and water (65:35, v/v), a flow rate of 1.6mLmin(-1), a sample volume of 10μL and UV detection at 245nm. Three different sample matrices (Opti-MEM medium, Krebs perfusion liquid and tissue lysate) and their treatment (dilution, SPE) were considered. The validated method was applied for the analysis of 805 real samples arising from in vitro transcellular transport assays and in vivo organ perfusion experiments in order to evaluate the interaction of efavirenz with ATP-dependent drug efflux transporters. The lack of interaction of efavirenz with ABCB1, ABCG2 and ABCC2 transporters as well as technical aspects of this analysis, including the adhesion of efavirenz to the plastic materials and the stability of the drug during different tissue lysis approaches are discussed.
- MeSH
- ABC transportér z rodiny G, člen 2 metabolismus MeSH
- acetonitrily chemie MeSH
- benzoxaziny chemie metabolismus MeSH
- biologický transport fyziologie MeSH
- buněčné linie MeSH
- buňky MDCK MeSH
- krysa rodu rattus MeSH
- P-glykoprotein metabolismus MeSH
- perfuze MeSH
- placenta chemie MeSH
- potkani Wistar MeSH
- proteiny spojené s mnohočetnou rezistencí k lékům metabolismus MeSH
- psi MeSH
- reprodukovatelnost výsledků MeSH
- stabilita léku MeSH
- těhotenství MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- psi MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The hippocampus is important for learning tasks, such as conditioned place preference (CPP), which is widely used as a model for studying the reinforcing effects of drugs with dependence liability. Long-term opiate use may produce maladaptive plasticity in the brain structures involved in learning and memory, such as the hippocampus. We investigated the phenomenon of conditioning with morphine on the cell density of female rat hippocampus. Forty-eight female Wistar rats weighing on average 200-250 g were used. Rats were distributed into eight groups. Experimental groups received morphine daily (three days) at different doses (2.5, 5, 7.5 mg/kg) and the control-saline group received normal saline (1 ml/kg), and then the CPP test was performed. Three sham groups received only different doses (2.5, 5, 7.5 mg/kg) of morphine without CPP test. Forty-eight hours after behavioural testing animals were decapitated under chloroform anaesthesia and their brains were fixed, and after tissue processing, slices were stained with cresyl violet for neurons and phosphotungstic acid haematoxylin for astrocytes. The maximum response was obtained with 5 mg/kg of morphine. The density of neurons in CA1 and CA3 areas of hippocampus after injection of morphine and CPP was decreased. The number of astrocytes in different areas of hippocampus was increased after injection of morphine and CPP. It seems that the effective dose was 5 mg/kg, as it led to the CPP. We concluded that both injection of mor phine and CPP can decrease the density of neurons and also increase the number of astrocytes in the rat hippocampus.
- MeSH
- astrocyty cytologie účinky léků MeSH
- benzoxaziny chemie MeSH
- chování zvířat MeSH
- hematoxylin chemie MeSH
- hipokampus cytologie účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- kyselina fosfowolframová chemie MeSH
- lokomoce MeSH
- morfin MeSH
- neurony cytologie účinky léků MeSH
- podmiňování (psychologie) * MeSH
- potkani Wistar MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
N-(α-ketoacyl)anthranilic acids reacted with phenylhydrazinium chloride in boiling acetic acid to afford 2-(indol-2-carboxamido)benzoic acids in good to excellent yields and 2-indolyl-3,1-benzoxazin-4-ones as by-products. The formation of the latter products could easily be suppressed by a hydrolytic workup. Alternatively, by increasing the reaction temperature and/or time, 2-indolyl-3,1-benzoxazin-4-ones can be obtained exclusively. Optimisations of the reaction conditions as well as the scope and the course of the transformations were investigated. The products were characterized by (1)H, (13)C and (15)N NMR spectroscopy. The corresponding resonances were assigned on the basis of the standard 1D and gradient selected 2D NMR experiments ((1)H-(1)H gs-COSY, (1)H-(13)C gs-HSQC, (1)H-(13)C gs-HMBC) with (1)H-(15)N gs-HMBC as a practical tool to determine (15)N NMR chemical shifts at the natural abundance level of (15)N isotope.
Deriváty 3-fenyl-2H-1,3-benzoxazin-2,4(3H)-dionu jsou aktivní vůči Mycobacterium avium, pokud jsou substituovány v poloze 7 methylem. Jedna nebo dvě karbonylové skupiny musí být zaměněny za thioxo skupiny. Nejaktivnější sloučeniny nebyly substituovány na fenylu, nebo byly substituovány na fenylu v poloze 3 nebo 4 chlorem, bromem či methylem. Substituce v poloze 3 a 4 dvěma atomy chloru však aktivitu snižuje. Sloučeniny jsou aktivní vůči INH rezistentním kmenům. Připravili jsme dalších 44 derivátů s podobnou strukturou studovaným látkám, avšak s jiným substituentem v ploze 7 (chlor, brom, methoxy). Aktivita vůči M. avium byla nízká. Můžeme uzavřít, že se jedná o novou skupinu významně aktivních látek vůči Mycobacterium avium.
Derivatives of 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-dione are active against Mycobacterium avium when substituted in position 7 with a methyl. One or two carbonyl groups have to be replaced with a thioxo group. High active derivatives are the compounds without substitution on the phenyl, or those substituted on the phenyl in position 3 or 4 with chlorine, bromine or a methyl. The substitution in position 3 and 4 with two atoms of chlorine lowers the activity. The compounds are active against INH resistant strains. We synthesized other 44 derivatives with a similar structure of the compounds as in the paper but substituted in position 7 with other substituents (chlorine, bromine methoxy). The activity against M. avium was poor. It can be concluded that a new group of compounds with an excellent activity against M. avium has been found.
New 3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and 3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dithiones were synthesized. The compounds were tested for in vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium avium and two strains of Mycobacterium kansasii. The antimycobacterial activity increased with the replacement of the carbonyl group by the thiocarbonyl group in the starting 3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-diones. The most active derivatives were more active than isonicotinhydrazide (INH). Free-Wilson analysis was also carried out and the activity contribution was examined.
- MeSH
- antituberkulotika chemická syntéza chemie farmakologie MeSH
- benzoxaziny chemická syntéza chemie farmakologie MeSH
- isoniazid farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- Mycobacterium avium účinky léků MeSH
- Mycobacterium kansasii účinky léků MeSH
- Mycobacterium tuberculosis účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-one (DIMBOA) was isolated from maize phloem sap as a compound enhancing the degradation of isopentenyl adenine by maize cytokinin dehydrogenase (CKX), after oxidative conversion by either laccase or peroxidase. Laccase and peroxidase catalyze oxidative cleavage of DIMBOA to 4-nitrosoresorcinol-1-monomethyl ether (coniferron), which serves as a weak electron acceptor of CKX. The oxidation of DIMBOA and coniferron generates transitional free radicals that are used by CKX as effective electron acceptors. The function of free radicals in the CKX-catalyzed reaction was also verified with a stable free radical of 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid. Application of exogenous cytokinin to maize seedlings resulted in an enhanced benzoxazinoid content in maize phloem sap. The results indicate a new function for DIMBOA in the metabolism of the cytokinin group of plant hormones.
- MeSH
- benzoxaziny chemie metabolismus MeSH
- biokatalýza MeSH
- cytokininy metabolismus MeSH
- floém enzymologie MeSH
- kukuřice setá enzymologie MeSH
- lakasa metabolismus MeSH
- molekulární struktura MeSH
- oxidace-redukce MeSH
- oxidoreduktasy metabolismus MeSH
- peroxidasa metabolismus MeSH
- volné radikály metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The flavoenzyme cytokinin dehydrogenase (CKX) catalyzes an irreversible deactivation of plant hormones cytokinins through oxidative cleavage of the cytokinin side chain to yield adenine or adenosine and an aldehyde. In the catalytic cycle of CKX, the cytokinin-reduced flavin cofactor is reoxidized by a suitable electron acceptor. We have recently demonstrated that the oxidation products of natural hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) function as effective electron acceptors of apoplastic CKX from maize. The stable oxidation product of DIMBOA reacting with peroxidase or laccase was identified as 4-nitrosoresorcinol 1-monomethyl ether (coniferron), which, however, is only a weak electron acceptor of CKX. Further analyses suggested formation of transient free radicals that were estimated to reoxidize the cytokinin-reduced flavin cofactor of CKX with the rates comparable to those of flavin reduction.
