RESUMEN
(R)-PFI-2 is a histone substrate-competitive inhibitor of the human histone lysine monomethyltransferase SETD7. Aimed at developing potent inhibitors of SETD7 that can also act as small molecule substrates, we replaced the pyrrolidine ring of (R)-PFI-2 with several side chains bearing nucleophilic functional groups. We explored the inhibitory activity of 20 novel (R)-PFI-2 analogues, and found that the most potent analogue has a hydroxyethyl side chain (7). SETD7's ability to catalyse methylation of (R)-PFI-2-based small molecules was evaluated by mass spectrometric assays, and we observed efficient methylation of analogues bearing lysine mimicking nucleophilic amines. The optimal side chain was found to be an aminoethyl group (1), which was surprisingly also dimethylated by SETD7. The work demonstrates that small molecules can act as both substrates and inhibitors of biomedically important SETD7.
Asunto(s)
N-Metiltransferasa de Histona-Lisina , Histonas , Humanos , Lisina , Pirrolidinas/farmacología , Pirrolidinas/químicaRESUMEN
Methylation of lysine residues in histone proteins is catalyzed by S-adenosylmethionine (SAM)-dependent histone lysine methyltransferases (KMTs), a genuinely important class of epigenetic enzymes of biomedical interest. Here we report synthetic, mass spectrometric, NMR spectroscopic and quantum mechanical/molecular mechanical (QM/MM) molecular dynamics studies on KMT-catalyzed methylation of histone peptides that contain lysine and its sterically demanding analogs. Our synergistic experimental and computational work demonstrates that human KMTs have a capacity to catalyze methylation of slightly bulkier lysine analogs, but lack the activity for analogs that possess larger aromatic side chains. Overall, this study provides an important chemical insight into molecular requirements that contribute to efficient KMT catalysis and expands the substrate scope of KMT-catalyzed methylation reactions.
Asunto(s)
N-Metiltransferasa de Histona-Lisina/química , Lisina/química , Catálisis , Dominio Catalítico , HumanosRESUMEN
We report synthesis and enzymatic assays on human histone lysine methyltransferase catalysed methylation of histones that possess lysine and its geometrically constrained analogues containing rigid (E)-alkene (KE), (Z)-alkene (KZ) and alkyne (Kyne) moieties. Methyltransferases G9a and GLP do have a capacity to catalyse methylation in the order K â« KE > KZ â¼ Kyne, whereas monomethyltransferase SETD8 catalyses only methylation of K and KE.
Asunto(s)
N-Metiltransferasa de Histona-Lisina/metabolismo , Lisina/metabolismo , Alquenos/química , Alquenos/metabolismo , Alquinos/química , Alquinos/metabolismo , Biocatálisis , Humanos , Lisina/análogos & derivados , Lisina/química , Metilación , Conformación MolecularRESUMEN
Malaria eradication is critically dependent on new therapeutics that target resistant Plasmodium parasites and block transmission of the disease. Here, we report that pantothenamide bioisosteres were active against blood-stage Plasmodium falciparum parasites and also blocked transmission of sexual stages to the mosquito vector. These compounds were resistant to degradation by serum pantetheinases, showed favorable pharmacokinetic properties, and cleared parasites in a humanized mouse model of P. falciparum infection. Metabolomics revealed that coenzyme A biosynthetic enzymes converted pantothenamides into coenzyme A analogs that interfered with parasite acetyl-coenzyme A anabolism. Resistant parasites generated in vitro showed mutations in acetyl-coenzyme A synthetase and acyl-coenzyme A synthetase 11. Introduction and reversion of these mutations in P. falciparum using CRISPR-Cas9 gene editing confirmed the roles of these enzymes in the sensitivity of the malaria parasites to pantothenamides. These pantothenamide compounds with a new mode of action may have potential as drugs against malaria parasites.
Asunto(s)
Acetilcoenzima A/biosíntesis , Antimaláricos/farmacología , Vías Biosintéticas/efectos de los fármacos , Ácido Pantoténico/análogos & derivados , Ácido Pantoténico/farmacología , Plasmodium falciparum/metabolismo , Animales , Antimaláricos/química , Antimaláricos/farmacocinética , Modelos Animales de Enfermedad , Resistencia a Medicamentos/efectos de los fármacos , Humanos , Malaria Falciparum/parasitología , Malaria Falciparum/transmisión , Masculino , Ratones Endogámicos BALB C , Mutación/genética , Ácido Pantoténico/química , Parasitemia/tratamiento farmacológico , Parásitos/efectos de los fármacos , Parásitos/metabolismo , Proteínas Protozoarias/genética , Reproducción Asexuada/efectos de los fármacos , Resultado del Tratamiento , Trofozoítos/efectos de los fármacos , Trofozoítos/metabolismoRESUMEN
The emergence of multidrug resistant bacteria has prioritized the development of new antibiotics. N-substituted pantothenamides, analogs of the natural compound pantetheine, were reported to target bacterial coenzyme A biosynthesis, but these compounds have never reached the clinic due to their instability in biological fluids. Plasma-stable pantothenamide analogs could overcome these issues. We first synthesized a number of bioisosteres of the prototypic pantothenamide N7-Pan. A compound with an inverted amide bond (CXP18.6-012) was found to provide plasma-stability with minimal loss of activity compared to the parent compound N7-Pan. Next, we synthesized inverted pantothenamides with a large variety of side chains. Among these we identified a number of novel stable inverted pantothenamides with selective activity against Gram-positive bacteria such as staphylococci and streptococci, at low micromolar concentrations. These data provide future direction for the development of pantothenamides with clinical potential.
Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Staphylococcus/efectos de los fármacos , Streptococcus/efectos de los fármacos , Antibacterianos/química , Estabilidad de Medicamentos , Pruebas de Sensibilidad Microbiana , Estructura MolecularRESUMEN
SETD7 is a histone H3K4 lysine methyltransferase involved in human gene regulation. Aberrant expression of SETD7 has been associated with various diseases, including cancer. Therefore, SETD7 is considered a good target for the development of new epigenetic drugs. To date, few selective small-molecule inhibitors have been reported that target SETD7, the most potent being (R)-PFI-2. Herein we report structure-activity relationship studies on (R)-PFI-2 and its analogues. A library of 29 structural analogues of (R)-PFI-2 was synthesized and evaluated for inhibition of recombinantly expressed human SETD7. The key interactions were found to be a salt bridge and a hydrogen bond formed between (R)-PFI-2's NH2+ group and SETD7's Asp256 and His252 residue, respectively.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , Pirrolidinas/química , Pirrolidinas/farmacología , Sulfonamidas/química , Sulfonamidas/farmacología , Tetrahidroisoquinolinas/química , Tetrahidroisoquinolinas/farmacología , Inhibidores Enzimáticos/síntesis química , Epigénesis Genética/efectos de los fármacos , N-Metiltransferasa de Histona-Lisina/química , N-Metiltransferasa de Histona-Lisina/metabolismo , Humanos , Simulación del Acoplamiento Molecular , Pirrolidinas/síntesis química , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Tetrahidroisoquinolinas/síntesis químicaRESUMEN
BACKGROUND: A number of synthetic pantothenate derivatives, such as pantothenamides, are known to inhibit the growth of the human malaria parasite Plasmodium falciparum, by interfering with the parasite Coenzyme A (CoA) biosynthetic pathway. The clinical use of pantothenamides is limited by their sensitivity to breakdown by ubiquitous human pantetheinases of the vanin family. METHODS: A number of pantothenate derivatives (pantothenones) with potent and specific inhibitory activity against mammalian vanins were tested in a proliferation assay of asexual P. falciparum blood stages alone, and in combination with pantothenamides. RESULTS: The vanin inhibitors were found to protect pantothenamides against breakdown by plasma vanins, thereby preserving the in vitro anti-malarial activity. Moreover, some of the vanin inhibitors showed in vitro anti-malarial activity in the low micromolar range. The most potent antimalarial in this series of compounds (RR8), was found to compete with pantothenate in a combination proliferation assay. No correlation, however, was found between anti-vanin and anti-malarial activity, nor was pantetheinase activity detected in P. falciparum extracts. CONCLUSIONS: Growth inhibition is most likely due to competition with pantothenate, rather than pantetheinase inhibition. As vanin inhibitors of the pantothenone class are stable in biological fluids and are non-toxic to mammalian cells, they may represent novel pantothenate-based anti-malarials, either on their own or in combination with pantothenamides.
Asunto(s)
Antimaláricos/uso terapéutico , Ácido Pantoténico/uso terapéutico , Antimaláricos/química , Antimaláricos/farmacología , Humanos , Malaria Falciparum/tratamiento farmacológico , Ácido Pantoténico/análogos & derivados , Ácido Pantoténico/farmacología , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/crecimiento & desarrolloRESUMEN
The emergence of resistance against current antibiotics calls for the development of new compounds to treat infectious diseases. Synthetic pantothenamides are pantothenate analogs that possess broad-spectrum antibacterial activity in vitro in minimal media. Pantothenamides were shown to be substrates of the bacterial coenzyme A (CoA) biosynthetic pathway, causing cellular CoA depletion and interference with fatty acid synthesis. In spite of their potential use and selectivity for bacterial metabolic routes, these compounds have never made it to the clinic. In the present study, we show that pantothenamides are not active as antibiotics in the presence of serum, and we found that they were hydrolyzed by ubiquitous pantetheinases of the vanin family. To address this further, we synthesized a series of pantetheinase inhibitors based on a pantothenate scaffold that inhibited serum pantetheinase activity in the nanomolar range. Mass spectrometric analysis showed that addition of these pantetheinase inhibitors prevented hydrolysis of pantothenamides by serum. We found that combinations of these novel pantetheinase inhibitors and prototypic pantothenamides like N5-Pan and N7-Pan exerted antimicrobial activity in vitro, particularly against Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes) even in the presence of serum. These results indicate that pantothenamides, when protected against degradation by host pantetheinases, are potentially useful antimicrobial agents.
Asunto(s)
Antibacterianos/farmacología , Bacterias Grampositivas/efectos de los fármacos , Ácido Pantoténico/farmacología , Antibacterianos/química , Pruebas de Sensibilidad Microbiana , Ácido Pantoténico/análogos & derivados , Ácido Pantoténico/química , Staphylococcus aureus/efectos de los fármacos , Streptococcus pneumoniae/efectos de los fármacos , Streptococcus pyogenes/efectos de los fármacosRESUMEN
Vanins are enzymes with pantetheinase activity and are presumed to play a role in the recycling of pantothenic acid (vitamin B5) from pantetheine. Pantothenic acid is an essential nutrient required to synthesize coenzyme A, a cofactor involved in many biological processes such as fatty acid synthesis and oxidation of pyruvate to fuel the citric acid cycle. Hydrolysis of pantetheine also liberates cysteamine, a known antioxidant. Vanin-1 is highly expressed in liver and is under transcriptional control of PPAR-α and nutritional status, suggesting a role in energy metabolism. The lack of potent and specific inhibitors of vanins has hampered detailed investigation of their function. We hereby report the design, synthesis, and characterization of a novel pantetheine analogue, RR6, that acts as a selective, reversible, and competitive vanin inhibitor at nanomolar concentration. Oral administration of RR6 in rats completely inhibited plasma vanin activity and caused alterations of plasma lipid concentrations upon fasting, thereby illustrating its potential use in chemical biology research.
Asunto(s)
Amidohidrolasas/antagonistas & inhibidores , Descubrimiento de Drogas , Panteteína/farmacología , Bibliotecas de Moléculas Pequeñas/farmacología , Amidohidrolasas/metabolismo , Animales , Bovinos , Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Proteínas Ligadas a GPI/antagonistas & inhibidores , Proteínas Ligadas a GPI/metabolismo , Humanos , Masculino , Estructura Molecular , Panteteína/análogos & derivados , Panteteína/química , Ratas , Ratas Wistar , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química , Relación Estructura-ActividadRESUMEN
Bacillus cereus produces the emetic toxin cereulide, a cyclic dodecadepsipeptide that can act as a K(+) ionophore, dissipating the transmembrane potential in mitochondria of eukaryotic cells. Because pure cereulide has not been commercially available, cereulide content in food samples has been expressed in valinomycin equivalents, a highly similar cyclic potassium ionophore that is commercially available. This research tested the biological activity of synthetic cereulide and validated its use as a standard in the quantification of cereulide contents in food samples. The synthesis route consists of 10 steps that result in a high yield of synthetic cereulide that showed biological activity in the HEp-2 cell assay and the boar sperm motility assay. The activity is different in both methods, which may be attributed to differences in K(+) content of the test media used. Using cereulide or valinomycin as a standard to quantify cereulide based on liquid chromatography-mass spectrometry (LC-MS), the concentration determined with cereulide as a standard was on average 89.9% of the concentration determined using valinomycin as a standard. The recovery experiments using cereulide-spiked food products and acetonitrile as extraction solute showed that the LC-MS method with cereulide as a standard is a reliable and accurate method to quantify cereulide in food, because the recovery rate was close to 100% over a wide concentration range.
Asunto(s)
Cromatografía Liquida/métodos , Depsipéptidos/análisis , Eméticos/análisis , Análisis de los Alimentos/métodos , Espectrometría de Masas/métodos , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cromatografía Liquida/normas , Depsipéptidos/síntesis química , Depsipéptidos/toxicidad , Eméticos/síntesis química , Eméticos/toxicidad , Hepatocitos/efectos de los fármacos , Humanos , Locomoción/efectos de los fármacos , Masculino , Espectrometría de Masas/normas , Estándares de Referencia , Espermatozoides/efectos de los fármacos , Sus scrofaRESUMEN
Two complementary strategies for the synthesis of febrifugine are detailed based on previously developed chemoenzymatic approaches to the 3-hydroxypiperidine skeleton. The introduction of the quinazolone-containing side chain in both strategies was based on an N-acyliminium ion-mediated coupling reaction.
Asunto(s)
Piperidinas/síntesis química , Quinazolinas/síntesis química , Catálisis , Piperidinas/química , Quinazolinas/química , Estereoisomerismo , Especificidad por SustratoRESUMEN
In 2003, we reported the isolation, structure elucidation, and pharmacology of epiquinamide (1), a novel alkaloid isolated from an Ecuadoran poison frog, Epipedobates tricolor. Since then, several groups, including ours, have undertaken synthetic efforts to produce this compound, which appeared initially to be a novel, beta2-selective nicotinic acetylcholine receptor agonist. Based on prior chiral GC analysis of synthetic and natural samples, the absolute structure of this alkaloid was established as (1S,9aS)-1-acetamidoquinolizidine. We have synthesized the (1R*,9aS*)-isomer (epi-epiquinamide) using an iminium ion nitroaldol reaction as the key step. We have also synthesized ent-1 semisynthetically from (-)-lupinine. Synthetic epiquinamide is inactive at nicotinic receptors, in accord with recently published reports. We have determined that the activity initially reported is due to cross-contamination from co-occurring epibatidine in the isolated material.
Asunto(s)
Alcaloides , Quinolizinas , Ranidae/metabolismo , Receptores Nicotínicos/efectos de los fármacos , Alcaloides/síntesis química , Alcaloides/química , Alcaloides/aislamiento & purificación , Alcaloides/toxicidad , Venenos de Anfibios/síntesis química , Venenos de Anfibios/química , Venenos de Anfibios/aislamiento & purificación , Venenos de Anfibios/toxicidad , Animales , Cromatografía de Gases y Espectrometría de Masas , Estructura Molecular , Quinolizinas/síntesis química , Quinolizinas/química , Quinolizinas/aislamiento & purificación , Quinolizinas/toxicidad , Esparteína/análogos & derivados , Esparteína/síntesis química , Esparteína/química , Esparteína/economía , EstereoisomerismoRESUMEN
A stereoselective synthesis of (+)-epiquinamide is presented in combination with determination of the absolute configuration of the natural product. Key steps in the sequence involved chemoenzymatic formation of an enantiomerically pure cyanohydrin, reductive cyclization to the corresponding cyclic N,N-acetal, and subsequent conversion into a suitable N-acyliminium ion precursor to enable construction of the second ring.
Asunto(s)
Acetales/química , Cationes/química , Iminas/química , Quinolizinas/síntesis química , Animales , Anuros , Productos Biológicos/síntesis química , Productos Biológicos/química , Quinolizinas/química , Estereoisomerismo , Especificidad por SustratoRESUMEN
A seven-step synthesis of orthogonally O-protected 2-deoxy-streptamine has been developed from readily available neomycin, with an overall yield of 28%. Key chemical transformations include a chemoselective glycosidic bond hydrolysis and two regioselective protective group manipulations involving acetylation and deacetylation. The synthetic route is amenable to scale-up for the production of multigram quantities of enantiopure and orthogonally O-protected 2-deoxystreptamine, a versatile scaffold for the generation of libraries of RNA-targeting ligands.
Asunto(s)
Química Orgánica/métodos , Hexosaminas/síntesis química , Hexosaminas/química , Hidrólisis , Espectroscopía de Resonancia Magnética , Neomicina/químicaRESUMEN
[reaction: see text] Herein, we report a short and diastereoselective synthesis of the natural product (-)-dysibetaine PP. The key step in the synthetic sequence is a novel highly diastereoselective tandem-cyclization reaction of an enantiomerically pure dipeptide. This cyclization methodology is applied in the synthesis of a broader range of N-heterocyclic scaffolds.
Asunto(s)
Pirrolidinonas/síntesis química , Animales , Ciclización , Dipéptidos/química , Conformación Molecular , Estructura Molecular , Poríferos/química , EstereoisomerismoRESUMEN
This article provides an overview of the literature concerning synthetic applications of unsaturated aliphatic amino acids in the period May 2000 to December 2004.
Asunto(s)
Aminoácidos/síntesis química , Química Orgánica/métodos , Aminoácidos de Cadena Ramificada/síntesis química , Indicadores y Reactivos , Estructura Molecular , Unión Proteica , Conformación Proteica , EstereoisomerismoRESUMEN
The stereoselective total synthesis of the novel quinolizidine alkaloid (+)-epiquinamide is presented, starting from the amino acid l-allysine ethylene acetal. Key steps in the synthesis involved a highly diastereoselective N-acyliminium ion allylation and a ring-closing metathesis reaction to provide the bicyclic skeleton. [reaction: see text]
Asunto(s)
Alcaloides/síntesis química , Quinolizinas/síntesis química , Alcaloides/química , Ciclización , Conformación Molecular , Estructura Molecular , Quinolizinas/química , EstereoisomerismoRESUMEN
[reaction: see text] Herein, we report a diastereoselective synthesis of the natural product (2S,5R)-5-hydroxypipecolic acid and 6-substituted derivatives thereof. The key step in the synthetic sequence is a novel highly diastereoselective epoxidation reaction of an enantiomerically pure cyclic enamide intermediate.
Asunto(s)
Ácidos Pipecólicos/síntesis química , Cristalografía por Rayos X , Modelos Moleculares , Conformación Molecular , Ácidos Pipecólicos/química , EstereoisomerismoRESUMEN
[structure: see text] An expedient, high-yielding synthesis of two types of triazole-linked glycopeptides is described. These novel and stable glycopeptide mimics were prepared via Cu(I)-catalyzed [3 + 2] cycloaddition of either azide-functionalized glycosides and acetylenic amino acids or acetylenic glycosides and azide-containing amino acids.