RÉSUMÉ
Among arthropod vectors, ticks transmit the most diverse human and animal pathogens, leading to an increasing number of new challenges worldwide. Here we sequenced and assembled high-quality genomes of six ixodid tick species and further resequenced 678 tick specimens to understand three key aspects of ticks: genetic diversity, population structure, and pathogen distribution. We explored the genetic basis common to ticks, including heme and hemoglobin digestion, iron metabolism, and reactive oxygen species, and unveiled for the first time that genetic structure and pathogen composition in different tick species are mainly shaped by ecological and geographic factors. We further identified species-specific determinants associated with different host ranges, life cycles, and distributions. The findings of this study are an invaluable resource for research and control of ticks and tick-borne diseases.
Sujet(s)
Variation génétique/génétique , Maladies transmises par les tiques/microbiologie , Tiques/génétique , Animaux , Lignée cellulaire , Vecteurs de maladies , Spécificité d'hôte/génétiqueRÉSUMÉ
Small-molecule mimetics of the ß-hairpin flap of HIV-1 protease (HIV-1 PR) were designed based on a 1,4-benzodiazepine scaffold as a strategy to interfere with the flap-flap protein-protein interaction, which functions as a gated mechanism to control access to the active site. Michaelis-Menten kinetics suggested our small-molecules are competitive inhibitors, which indicates the mode of inhibition is through binding the active site or sterically blocking access to the active site and preventing flap closure, as designed. More generally, a new bioactive scaffold for HIV-1PR inhibition has been discovered, with the most potent compound inhibiting the protease with a modest K(i) of 11 µM.
Sujet(s)
Inhibiteurs de protéase du VIH/synthèse chimique , Protéase du VIH/composition chimique , Bibliothèques de petites molécules/composition chimique , Benzodiazépines/composition chimique , Benzodiazépines/métabolisme , Benzodiazépines/pharmacologie , Domaine catalytique , Survie cellulaire/effets des médicaments et des substances chimiques , Conception de médicament , Protéase du VIH/génétique , Protéase du VIH/métabolisme , Inhibiteurs de protéase du VIH/métabolisme , Inhibiteurs de protéase du VIH/pharmacologie , VIH-1 (Virus de l'Immunodéficience Humaine de type 1)/enzymologie , VIH-1 (Virus de l'Immunodéficience Humaine de type 1)/physiologie , Humains , Concentration inhibitrice 50 , Cinétique , Liaison aux protéines , Structure secondaire des protéines , Protéines recombinantes/biosynthèse , Protéines recombinantes/composition chimique , Bibliothèques de petites molécules/métabolisme , Bibliothèques de petites molécules/pharmacologie , Relation structure-activité , Réplication virale/effets des médicaments et des substances chimiquesRÉSUMÉ
The plasmepsins are specific aspartic proteases of the malaria parasite and a potential target for developing new antimalarial agents. Our previously reported peptidomimetic plasmepsin inhibitor with modified 2-aminoethylamino substituent, KNI-10740, was tested against chloroquine sensitive Plasmodium falciparum, D6, to be highly potent, however, the inhibitor exhibited about 5 times less activity against multi-drug resistant parasite (TM91C235). We hypothesized the potency reduction resulted from structural similarity between 2-aminoethylamino substituent of KNI-10740 and chloroquine. Then, we modified the moiety and finally identified compound 15d (KNI-10823), that could avoid drug-resistant mechanism of TM91C235 strain.
Sujet(s)
Antipaludiques/pharmacologie , Aspartic acid endopeptidases/antagonistes et inhibiteurs , Chloroquine/pharmacologie , Multirésistance aux médicaments/effets des médicaments et des substances chimiques , Plasmodium falciparum/effets des médicaments et des substances chimiques , Inhibiteurs de protéases/pharmacologie , Antipaludiques/synthèse chimique , Antipaludiques/composition chimique , Aspartic acid endopeptidases/métabolisme , Chloroquine/composition chimique , Relation dose-effet des médicaments , Structure moléculaire , Tests de sensibilité parasitaire , Inhibiteurs de protéases/synthèse chimique , Inhibiteurs de protéases/composition chimique , Relation structure-activitéRÉSUMÉ
We report the design and synthesis of a series of dipeptide-type inhibitors with novel P3 scaffolds that display potent inhibitory activity against SARS-CoV 3CLpro. A docking study involving binding between the dipeptidic lead compound 4 and 3CLpro suggested the modification of a structurally flexible P3 N-(3-methoxyphenyl)glycine with various rigid P3 moieties in 4. The modifications led to the identification of several potent derivatives, including 5c-k and 5n with the inhibitory activities (Ki or IC50) in the submicromolar to nanomolar range. Compound 5h, in particular, displayed the most potent inhibitory activity, with a Ki value of 0.006 µM. This potency was 65-fold higher than the potency of the lead compound 4 (Ki=0.39 µM). In addition, the Ki value of 5h was in very good agreement with the binding affinity (16 nM) observed in isothermal titration calorimetry (ITC). A SAR study around the P3 group in the lead 4 led to the identification of a rigid indole-2-carbonyl unit as one of the best P3 moieties (5c). Further optimization showed that a methoxy substitution at the 4-position on the indole unit was highly favorable for enhancing the inhibitory potency.
Sujet(s)
Conception de médicament , Inhibiteurs de protéases , Virus du SRAS/enzymologie , Protéines virales/antagonistes et inhibiteurs , Protéases 3C des coronavirus , Cysteine endopeptidases/métabolisme , Activation enzymatique/effets des médicaments et des substances chimiques , Concentration inhibitrice 50 , Simulation de docking moléculaire , Inhibiteurs de protéases/synthèse chimique , Inhibiteurs de protéases/composition chimique , Inhibiteurs de protéases/pharmacologie , Relation structure-activité , Protéines virales/métabolismeRÉSUMÉ
This work describes the design, synthesis, and evaluation of low-molecular weight peptidic SARS-CoV 3CL protease inhibitors. The inhibitors were designed based on the potent tripeptidic Z-Val-Leu-Ala(pyrrolidone-3-yl)-2-benzothiazole (8; Ki = 4.1 nM), in which the P3 valine unit was substituted with a variety of distinct moieties. The resulting series of dipeptide-type inhibitors displayed moderate to good inhibitory activities against 3CL(pro). In particular, compounds 26m and 26n exhibited good inhibitory activities with Ki values of 0.39 and 0.33 µM, respectively. These low-molecular weight compounds are attractive leads for the further development of potent peptidomimetic inhibitors with pharmaceutical profiles. Docking studies were performed to model the binding interaction of the compound 26m with the SARS-CoV 3CL protease. The preliminary SAR study of the peptidomimetic compounds with potent inhibitory activities revealed several structural features that boosted the inhibitory activity: (i) a benzothiazole warhead at the S1' position, (ii) a γ-lactam unit at the S1-position, (iii) an appropriately hydrophobic leucine moiety at the S2-position, and (iv) a hydrogen bond between the N-arylglycine unit and a backbone hydrogen bond donor at the S3-position.
Sujet(s)
Inhibiteurs de la cystéine protéinase/pharmacologie , Dipeptides/pharmacologie , Conception de médicament , Protéines virales/antagonistes et inhibiteurs , Protéases 3C des coronavirus , Cysteine endopeptidases/métabolisme , Inhibiteurs de la cystéine protéinase/synthèse chimique , Inhibiteurs de la cystéine protéinase/composition chimique , Dipeptides/synthèse chimique , Dipeptides/composition chimique , Relation dose-effet des médicaments , Humains , Modèles moléculaires , Conformation moléculaire , Masse moléculaire , Virus du SRAS/effets des médicaments et des substances chimiques , Virus du SRAS/enzymologie , Relation structure-activité , Protéines virales/métabolismeRÉSUMÉ
We describe here the design, synthesis and biological evaluation of a series of molecules toward the development of novel peptidomimetic inhibitors of SARS-CoV 3CL(pro). A docking study involving binding between the initial lead compound 1 and the SARS-CoV 3CL(pro) motivated the replacement of a thiazole with a benzothiazole unit as a warhead moiety at the P1' site. This modification led to the identification of more potent derivatives, including 2i, 2k, 2m, 2o, and 2p, with IC(50) or K(i) values in the submicromolar to nanomolar range. In particular, compounds 2i and 2p exhibited the most potent inhibitory activities, with K(i) values of 4.1 and 3.1 nM, respectively. The peptidomimetic compounds identified through this process are attractive leads for the development of potential therapeutic agents against SARS. The structural requirements of the peptidomimetics with potent inhibitory activities against SARS-CoV 3CL(pro) may be summarized as follows: (i) the presence of a benzothiazole warhead at the S1'-position; (ii) hydrogen bonding capabilities at the cyclic lactam of the S1-site; (iii) appropriate stereochemistry and hydrophobic moiety size at the S2-site and (iv) a unique folding conformation assumed by the phenoxyacetyl moiety at the S4-site.
Sujet(s)
Conception de médicament , Oligopeptides/synthèse chimique , Inhibiteurs de protéases/synthèse chimique , Protéines virales/antagonistes et inhibiteurs , Benzothiazoles/composition chimique , Sites de fixation , Cysteine endopeptidases/composition chimique , Cysteine endopeptidases/métabolisme , Liaison hydrogène , Simulation de docking moléculaire , Oligopeptides/composition chimique , Oligopeptides/métabolisme , Inhibiteurs de protéases/composition chimique , Inhibiteurs de protéases/métabolisme , Liaison aux protéines , Structure tertiaire des protéines , Virus du SRAS/métabolisme , Relation structure-activité , Protéines virales/métabolismeRÉSUMÉ
Kinetic analysis of the mode of inhibition of cathepsin L by KGP94, a lead compound from a privileged library of functionalized benzophenone thiosemicarbazone derivatives, demonstrated that it is a time-dependent, reversible, and competitive inhibitor of the enzyme. These results are consistent with the formation of a transient covalent bond, and are supported by molecular modeling that places the thiocarbonyl of the inhibitor in proximity to the thiolate moiety of the enzyme active site Cys25. KGP94 significantly decreased the activity of cathepsin L toward human type I collagen, and impeded both migration and invasion of MDA-MB-231 human breast cancer cells. Growth retardation was achieved in vivo against both recently implanted and established tumours using a C3H mouse mammary carcinoma model.
Sujet(s)
Antinéoplasiques/pharmacologie , Cathepsine L/antagonistes et inhibiteurs , Inhibiteurs de la cystéine protéinase/pharmacologie , Tumeurs expérimentales de la mamelle/traitement médicamenteux , Thiosemicarbazones/pharmacologie , Thiourée/analogues et dérivés , Animaux , Antinéoplasiques/composition chimique , Cathepsine L/métabolisme , Lignée cellulaire tumorale , Mouvement cellulaire/effets des médicaments et des substances chimiques , Prolifération cellulaire/effets des médicaments et des substances chimiques , Inhibiteurs de la cystéine protéinase/composition chimique , Modèles animaux de maladie humaine , Relation dose-effet des médicaments , Évaluation préclinique de médicament , Femelle , Cellules endothéliales de la veine ombilicale humaine/effets des médicaments et des substances chimiques , Humains , Tumeurs expérimentales de la mamelle/anatomopathologie , Souris , Lignées consanguines de souris , Modèles moléculaires , Structure moléculaire , Relation structure-activité , Thiosemicarbazones/composition chimique , Thiourée/composition chimique , Thiourée/pharmacologieRÉSUMÉ
Mining and mineral-processing wastes are one of the world's largest chronic waste concerns. Their reuse should be included in future sustainable development plans, but the potential impacts on a number of environmental processes are highly variable and must be thoroughly assessed. The chemical composition and geotechnical properties of the source rock determine which uses are most appropriate and whether reuse is economically feasible. If properly evaluated, mining waste can be reused to reextract minerals, provide additional fuel for power plants, supply construction materials, and repair surface and subsurface land structures altered by mining activities themselves.
RÉSUMÉ
A series of 36 thiosemicarbazone analogues containing the thiochromanone molecular scaffold functionalized primarily at the C-6 position were prepared by chemical synthesis and evaluated as inhibitors of cathepsins L and B. The most promising inhibitors from this group are selective for cathepsin L and demonstrate IC50 values in the low nanomolar range. In nearly all cases, the thiochromanone sulfide analogues show superior inhibition of cathepsin L as compared to their corresponding thiochromanone sulfone derivatives. Without exception, the compounds evaluated were inactive (IC50 > 10000 nM) against cathepsin B. The most potent inhibitor (IC50 = 46 nM) of cathepsin L proved to be the 6,7-difluoro analogue 4. This small library of compounds significantly expands the structure-activity relationship known for small molecule, nonpeptidic inhibitors of cathepsin L.
RÉSUMÉ
We used a combined approach of experiment and simulation to determine the helical population and folding pathway of a small helix forming blocked pentapeptide, Ac-(Ala)(5)-NH(2). Experimental structural characterization of this blocked peptide was carried out with far UV circular dichroism spectroscopy, FTIR, and NMR measurements. These measurements confirm the presence of the α-helical state in a buffer solution. Direct molecular dynamics and replica-exchange simulations of the pentapeptide were performed using several popular force fields with explicit solvent. The simulations yielded statistically reliable estimates of helix populations, melting curves, folding, and nucleation times. The distributions of conformer populations are used to measure folding cooperativity. Finally, a statistical analysis of the sample of helix-coil transition paths was performed. The details of the calculated helix populations, folding kinetics and pathways vary with the employed force field. Interestingly, the helix populations, folding, and unfolding times obtained from most of the studied force fields are in qualitative agreement with each other and with available experimental data, with the deviations corresponding to several kcal/mol in energy at 300 K. Most of the force fields also predict qualitatively similar transition paths, with unfolding initiated at the C-terminus. Accuracy of potential energy parameters, rather than conformational sampling may be the limiting factor in current molecular simulations.
Sujet(s)
Peptides/composition chimique , Dichroïsme circulaire/méthodes , Simulation numérique , Liaison hydrogène , Cinétique , Spectroscopie par résonance magnétique/méthodes , Conformation des protéines , Pliage des protéines , Structure secondaire des protéines , Structure tertiaire des protéines , Spectroscopie infrarouge à transformée de Fourier/méthodes , Température , Thermodynamique , Rayons ultravioletsRÉSUMÉ
A small library of 36 functionalized benzophenone thiosemicarbazone analogs has been prepared by chemical synthesis and evaluated for their ability to inhibit the cysteine proteases cathepsin L and cathepsin B. Inhibitors of cathepsins L and B have the potential to limit or arrest cancer metastasis. The six most active inhibitors of cathepsin L (IC50<85 nM) in this series incorporate a meta-bromo substituent in one aryl ring along with a variety of functional groups in the second aryl ring. These six analogs are selective for their inhibition of cathepsin L versus cathepsin B (IC50>10,000 nM). The most active analog in the series, 3-bromophenyl-2'-fluorophenyl thiosemicarbazone 1, also efficiently inhibits cell invasion of the DU-145 human prostate cancer cell line.
Sujet(s)
Cathepsine B/antagonistes et inhibiteurs , Cathepsine L/antagonistes et inhibiteurs , Inhibiteurs de la cystéine protéinase/synthèse chimique , Inhibiteurs de la cystéine protéinase/pharmacologie , Conception de médicament , Thiosemicarbazones/synthèse chimique , Thiosemicarbazones/pharmacologie , Domaine catalytique , Inhibiteurs de la cystéine protéinase/composition chimique , Humains , Concentration inhibitrice 50 , Modèles moléculaires , Structure moléculaire , Thiosemicarbazones/composition chimiqueRÉSUMÉ
A series of compounds bearing tetrahydronaphthalene, benzophenone, propiophenone, and related rigid molecular skeletons functionalized with thiosemicarbazone or unsaturated carbonyl moieties were prepared by chemical synthesis and evaluated for their ability to inhibit the enzyme cruzain. As potential treatment agents for Chagas' disease, three compounds from the group demonstrate potent inhibition of cruzain with IC(50) values of 17, 24, and 80 nM, respectively.