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1.
J Med Chem ; 63(23): 15050-15071, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33261314

RESUMO

Scaffold hopping and structure-based drug design were employed to identify substituted 4-aminoquinolines and 4-aminonaphthyridines as potent, small molecule inhibitors of tumor necrosis factor alpha (TNFα). Structure-activity relationships in both the quinoline and naphthyridine series leading to the identification of compound 42 with excellent potency and pharmacokinetic profile are discussed. X-ray co-crystal structure analysis and ultracentrifugation experiments clearly demonstrate that these inhibitors distort the TNFα trimer upon binding, leading to aberrant signaling when the trimer binds to TNF receptor 1 (TNFR1). Pharmacokinetic-pharmacodynamic activity of compound 42 in a TNF-induced IL-6 mouse model and in vivo activity in a collagen antibody-induced arthritis model, where it showed biologic-like in vivo efficacy, will be discussed.

2.
Bioorg Med Chem ; 28(22): 115723, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33007547

RESUMO

Myeloperoxidase (MPO) is a heme peroxidase found in neutrophils, monocytes and macrophages that efficiently catalyzes the oxidation of endogenous chloride into hypochlorous acid for antimicrobial activity. Chronic MPO activation can lead to indiscriminate protein modification causing tissue damage, and has been associated with chronic inflammatory diseases, atherosclerosis, and acute cardiovascular events. Triazolopyrimidine 5 is a reversible MPO inhibitor; however it suffers from poor stability in acid, and is an irreversible inhibitor of the DNA repair protein methyl guanine methyl transferase (MGMT). Structure-based drug design was employed to discover benzyl triazolopyridines with improved MPO potency, as well as acid stability, no reactivity with MGMT, and selectivity against thyroid peroxidase (TPO). Structure-activity relationships, a crystal structure of the MPO-inhibitor complex, and acute in vivo pharmacodynamic data are described herein.

3.
Bioorg Med Chem Lett ; 29(20): 126673, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31519373

RESUMO

A series of benzothiazoles with a cyano group was synthesized and evaluated as endothelial lipase (EL) inhibitors for the potential treatment of cardiovascular diseases. Efforts to reduce molecular weight and polarity in the series led to improved physicochemical properties of these compounds, as well as selectivity for EL over hepatic lipase (HL). As a benchmark compound, 8i demonstrated potent EL activity, an acceptable absorption, distribution, metabolism and elimination (ADME) profile and pharmacokinetic (PK) exposure which allowed further evaluation in preclinical animal efficacy studies.


Assuntos
Benzotiazóis/química , Doenças Cardiovasculares/tratamento farmacológico , Inibidores Enzimáticos/química , Lipase/antagonistas & inibidores , Animais , Benzotiazóis/farmacologia , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Lipase/genética , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade
4.
Acta Crystallogr D Struct Biol ; 72(Pt 5): 658-74, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27139629

RESUMO

The cytokine TGF-ß modulates a number of cellular activities and plays a critical role in development, hemostasis and physiology, as well as in diseases including cancer and fibrosis. TGF-ß signals through two transmembrane serine/threonine kinase receptors: TGFßR1 and TGFßR2. Multiple structures of the TGFßR1 kinase domain are known, but the structure of TGFßR2 remains unreported. Wild-type TGFßR2 kinase domain was refractory to crystallization, leading to the design of two mutated constructs: firstly, a TGFßR1 chimeric protein with seven ATP-site residues mutated to their counterparts in TGFßR2, and secondly, a reduction of surface entropy through mutation of six charged residues on the surface of the TGFßR2 kinase domain to alanines. These yielded apo and inhibitor-bound crystals that diffracted to high resolution (<2 Å). Comparison of these structures with those of TGFßR1 reveal shared ligand contacts as well as differences in the ATP-binding sites, suggesting strategies for the design of pan and selective TGFßR inhibitors.


Assuntos
Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/química , Receptores de Fatores de Crescimento Transformadores beta/antagonistas & inibidores , Receptores de Fatores de Crescimento Transformadores beta/química , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Humanos , Ligantes , Modelos Moleculares , Ligação Proteica , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Inibidores de Proteínas Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Fatores de Crescimento Transformadores beta/metabolismo
5.
Anal Biochem ; 501: 48-55, 2016 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-26925857

RESUMO

Monoacylglycerol acyltransferase 2 (MGAT2) is a membrane-bound lipid acyltransferase that catalyzes the formation of diacylglycerol using monoacylglycerol and fatty acyl CoA as substrates. MGAT2 is important for intestinal lipid absorption and is an emerging target for the treatment of metabolic diseases. In the current study, we identified and characterized four classes of novel MGAT2 inhibitors. We established both steady state and kinetic binding assay protocols using a novel radioligand, [(3)H]compound A. Diverse chemotypes of MGAT2 inhibitors were found to compete binding of [(3)H]compound A to MGAT2, indicating the broad utility of [(3)H]compound A for testing various classes of MGAT2 inhibitors. In the dynamic binding assays, the kinetic values of MGAT2 inhibitors such as Kon, Koff, and T1/2 were systematically defined. Of particular value, the residence times of inhibitors on MGAT2 enzyme were derived. We believe that the identification of novel classes of MGAT2 inhibitors and the detailed kinetic characterization provide valuable information for the identification of superior candidates for in vivo animal and clinical studies. The current work using a chemical probe to define inhibitory kinetics can be broadly applied to other membrane-bound acyltransferases.


Assuntos
Aciltransferases/antagonistas & inibidores , Aciltransferases/metabolismo , Ensaios Enzimáticos/métodos , Inibidores Enzimáticos/farmacologia , Animais , Avaliação Pré-Clínica de Medicamentos/métodos , Inibidores Enzimáticos/química , Humanos , Ligantes , Camundongos , Ligação Proteica/efeitos dos fármacos , Ensaio Radioligante/métodos , Ratos , Proteínas Recombinantes/metabolismo
6.
J Lipid Res ; 56(3): 747-53, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25598079

RESUMO

To demonstrate monoacylglycerol acyltransferase 2 (MGAT2)-mediated enzyme activity in a cellular context, cells of the murine secretin tumor cell-1 line of enteroendocrine origin were used to construct human MGAT2-expressing recombinant cell lines. Low throughput and utilization of radiolabeled substrate in a traditional TLC technique were circumvented by development of a high-resolution LC/MS platform. Monitoring incorporation of stable isotope-labeled D31-palmitate into diacylglycerol (DAG) allowed selective tracing of the cellular DAG synthesis activity. This assay format dramatically reduced background interference and increased the sensitivity and the signal window compared with the TLC method. Using this assay, several MGAT2 inhibitors from different chemotypes were characterized. The described cell-based assay adds a new methodology for the development and evaluation of MGAT2 inhibitors for the treatment of obesity and type 2 diabetes.


Assuntos
Bioensaio/métodos , Diglicerídeos/biossíntese , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , N-Acetilglucosaminiltransferases/antagonistas & inibidores , Animais , Linhagem Celular , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/enzimologia , Diabetes Mellitus Tipo 2/genética , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Camundongos , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Obesidade/tratamento farmacológico , Obesidade/enzimologia , Obesidade/genética , Ácido Palmítico/metabolismo
7.
Bioorg Med Chem Lett ; 21(1): 537-41, 2011 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21078556

RESUMO

Heterocyclic replacement of the isophthalamide phenyl ring in hydroxyethylamine (HEA) BACE-1 inhibitors was explored. A variety of indole-1,3-dicarboxamide HEAs exhibited potent BACE-1 enzyme inhibition, but displayed poor cellular activity. Improvements in cellular activity and aspartic protease selectivity were observed for 7-azaindole-1,3-dicarboxamide HEAs. A methylprolinol-bearing derivative (10n) demonstrated robust reductions in rat plasma Aß levels, but did not lower rat brain Aß due to poor central exposure. The same analog exhibited a high efflux ratio in a bidirectional Caco-2 assay and was likely a substrate of the efflux transporter P-glycoprotein. X-ray crystal structures are reported for two indole HEAs in complex with BACE-1.


Assuntos
Aminas/química , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Indóis/síntese química , Inibidores de Proteases/química , Piridinas/síntese química , Aminas/síntese química , Aminas/farmacologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/sangue , Animais , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Indóis/química , Indóis/farmacologia , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacologia , Estrutura Terciária de Proteína , Piridinas/química , Piridinas/farmacologia , Ratos , Relação Estrutura-Atividade
8.
Arch Biochem Biophys ; 445(1): 9-18, 2006 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-16364232

RESUMO

Dipeptidyl peptidase-IV (DPP-IV) is a serine protease with a signature Asp-His-Ser motif at the active site. Our pH data suggest that Gly-Pro-pNA cleavage catalyzed by DPP-IV is facilitated by an ionization of a residue with a pK of 7.2 +/- 0.1. By analogy to other serine proteases this pK is suggestive of His-Asp assisted Ser addition to the P1 carbonyl carbon of the substrate to form a tetrahedral intermediate. Solvent kinetic isotope effect studies yielded a D2Okcat/Km=2.9+/-0.2 and a D2Okcat=1.7+/-0.2 suggesting that kinetically significant proton transfers contribute to rate limitation during acyl intermediate formation (leaving group release) and hydrolysis. A "burst" of product release during pre steady-state Gly-Pro-pNA cleavage indicated rate limitation in the deacylation half-reaction. Nevertheless, the amplitude of the burst exceeded the enzyme concentration significantly (approximately 15-fold), which is consistent with a branching deacylation step. All of these data allowed us to better understand DPP-IV inhibition by saxagliptin (BMS-477118). We propose a two-step inhibition mechanism wherein an initial encounter complex is followed by covalent intermediate formation. Final inhibitory complex assembly (kon) depends upon the ionization of an enzyme residue with a pK of 6.2 +/- 0.1, and we assigned it to the catalytic His-Asp pair which enhances Ser nucleophilicity for covalent addition. An ionization with a pK of 7.9 +/- 0.2 likely reflects the P2 terminal amine of the inhibitor hydrogen bonding to Glu205/Glu206 in the enzyme active site. The formation of the covalent enzyme-inhibitor complex was reversible and dissociated with a koff of (5.5 +/- 0.4) x 10(-5) s(-1), thus yielding a Ki* (as koff/kon) of 0.35 nM, which is in good agreement with the value of 0.6 nM obtained from steady-state inhibition studies. Proton NMR spectra of DPP-IV showed a downfield resonance at 16.1 ppm. Two additional peaks in the 1H NMR spectra at 17.4 and 14.1 ppm were observed upon mixing the enzyme with saxagliptin. Fractionation factors (phi) of 0.6 and 0.5 for the 17.4 and 14.1 ppm peaks, respectively, are suggestive of short strong hydrogen bonds in the enzyme-inhibitor complex.


Assuntos
Adamantano/análogos & derivados , Dipeptídeos/química , Dipeptidil Peptidase 4/química , Inibidores Enzimáticos/química , Adamantano/química , Catálise , Humanos , Concentração de Íons de Hidrogênio , Cinética , Ressonância Magnética Nuclear Biomolecular , Solventes
9.
Arch Biochem Biophys ; 436(2): 367-76, 2005 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-15797249

RESUMO

Dipeptidyl peptidase-IV is a cell surface protease which plays an important role in glucose homeostasis through proteolytic inactivation of incretin hormones, primarily glucagon like peptide-1 (GLP-1). Substrate N-terminal amino acid (S2-S1) specificity is rather clearly defined, while no substantial information is available on the significance of amino acid interactions towards the C-terminus after the scissile bond (so called prime S1'-S4' or distant S5'-S28' sites). In the present study the increasing length of the peptide towards prime sites (S1'-S4') resulted in approximately 7-fold decrease in Km. Moreover, the Km for GLP-1 cleavage was comparable to that of an S2-S4' peptide, suggesting that few, if any, important enzyme-substrate interactions occur beyond the active site. Effect of substrate length on kcat was less obvious, but kcat/Km showed an increasing trend when His-Ala-pNA (representing the natural two N-terminal residues) was compared to GLP-1. To probe the impact of increasing substrate length on the free energy of activation (as has been suggested for elastase and chymotrypsin) we performed temperature studies. To adequately interpret thermodynamic data we sought to understand what steps limit the kcat expression. Steady-state parameters of the reactions catalyzed by serine proteases are composed of microscopic constants describing binding, acylation, and deacylation steps. Viscosity and pre-steady-state studies suggested that His-Ala-pNA cleavage is limited in the deacylation half-reaction, most likely the product release step. Thus, the free energy of activation, as calculated from the Eyring equation, is underestimated (at least for His-Ala-pNA) and the effect of substrate length on the acylation step (and transition-state stabilization) could not be unambiguously assessed.


Assuntos
Dipeptidil Peptidase 4/química , Sítios de Ligação , Ligação Competitiva , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Glucagon/química , Peptídeo 1 Semelhante ao Glucagon , Humanos , Hidrólise , Cinética , Modelos Químicos , Fragmentos de Peptídeos/química , Ligação Proteica , Precursores de Proteínas/química , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Especificidade por Substrato , Temperatura , Termodinâmica , Fatores de Tempo
10.
Arch Biochem Biophys ; 410(2): 307-16, 2003 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-12573291

RESUMO

Amyloid precursor protein (APP) cleaving enzyme (BACE) is the enzyme responsible for beta-site cleavage of APP, leading to the formation of the amyloid-beta peptide that is thought to be pathogenic in Alzheimer's disease (AD). Hence, BACE is an attractive pharmacological target, and numerous research groups have begun searching for potent and selective inhibitors of this enzyme as a potential mechanism for therapeutic intervention in AD. The mature enzyme is composed of a globular catalytic domain that is N-linked glycosylated in mammalian cells, a single transmembrane helix that anchors the enzyme to an intracellular membrane, and a short C-terminal domain that extends outside the phospholipid bilayer of the membrane. Here we have compared the substrate and active site-directed inhibitor binding properties of several recombinant constructs of human BACE. The constructs studied here address the importance of catalytic domain glycosylation state, inclusion of domains other than the catalytic domain, and incorporation into a membrane bilayer on the interactions of the enzyme active site with peptidic ligands. We find no significant differences in ligand binding properties among these various constructs. These data demonstrate that the nonglycosylated, soluble catalytic domain of BACE faithfully reflects the ligand binding properties of the full-length mature enzyme in its natural membrane environment. Thus, the use of the nonglycosylated, soluble catalytic domain of BACE is appropriate for studies aimed at understanding the determinants of ligand recognition by the enzyme active site.


Assuntos
Ácido Aspártico Endopeptidases/química , Proteínas Recombinantes/química , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide , Animais , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Células CHO , Catálise , Domínio Catalítico , Linhagem Celular , Membrana Celular/metabolismo , Cromatografia Líquida de Alta Pressão , Cricetinae , Relação Dose-Resposta a Droga , Drosophila , Endopeptidases , Escherichia coli/metabolismo , Glicosilação , Humanos , Concentração Inibidora 50 , Cinética , Ligantes , Luz , Bicamadas Lipídicas/metabolismo , Peptídeos/química , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/metabolismo , Espalhamento de Radiação , Fatores de Tempo
11.
J Med Chem ; 45(21): 4669-78, 2002 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-12361393

RESUMO

The identification of several potent pyrazole-based inhibitors of bacterial dihydroorotate dehydrogenase (DHODase) via a directed parallel synthetic approach is described below. The initial pyrazole-containing lead compounds were optimized for potency against Helicobacter pylori DHODase. Using three successive focused libraries, inhibitors were rapidly identified with the following characteristics: K(i) < 10 nM against H. pylori DHODase, sub-microg/mL H. pylori minimum inhibitory concentration activity, low molecular weight, and >10 000-fold selectivity over human DHODase.


Assuntos
Inibidores Enzimáticos/síntese química , Helicobacter pylori/efeitos dos fármacos , Oxirredutases/antagonistas & inibidores , Pirazóis/síntese química , Técnicas de Química Combinatória , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Helicobacter pylori/enzimologia , Humanos , Pirazóis/química , Pirazóis/farmacologia , Relação Estrutura-Atividade
12.
J Biol Chem ; 277(32): 28677-82, 2002 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-12029090

RESUMO

Pepsin inhibition by 3-alkoxy-4-arylpiperidine (substituted piperidine; (3R,4R)-3-(4-bromobenzyloxy)-4-[4-(2-naphthalen-1-yl-2-oxo-ethoxy)phenyl]piperidine) has been studied using steady-state kinetic and pre-equilibrium binding methods. Data were compared with pepstatin A, a well known competitive inhibitor of pepsin. Steady-state analysis reveals that the substituted piperidine likewise behaves as a competitive inhibitor. Pre-equilibrium binding studies indicate that the substituted piperidine can displace a fluorescently labeled statine inhibitor from the enzyme active site. Simulation of the stopped-flow fluorescence transients provided estimates of the K(d) values of 1.4 +/- 0.2 microm and 39 +/- 2 nm for the piperidine and the fluorescently labeled statine, respectively. The effects of combinations of these two inhibitors resulted in a series of parallel lines when plotted by the method of Yonetani and Theorell (Yonetani, T., and Theorell, H. (1964) Arch. Biochem. Biophys. 106, 234-251), suggesting that the two inhibitors bind in a mutually exclusive fashion to pepsin. Fitting of the entire data set to the appropriate equation yielded an alpha factor of 8 +/- 1. The magnitude of this factor ( infinity > alpha > 1) can be explained by a conformational distinction between the enzyme species that bind each inhibitor. The effects of pH on the inhibition constants for pepstatin A and the substituted piperidine also suggest that the inhibitors bind to distinct conformational forms of the enzyme. No inhibition by the piperidine was observed at acidic pH, while pepstatin A inhibition is maximal at low pH values. Inhibition by the piperidine was maximal when a group with pK 4.8 +/- 0.2 was deprotonated and another group with pK 5.9 +/- 0.2 was protonated. Most likely these two groups are the catalytic aspartates with perturbed ionization properties as a result of a significant and unique conformational change. Taken together, these data suggest that the enzyme can readily interconvert between two conformers, one capable of binding substrate and pepstatin A and the other capable of binding the substituted piperidine.


Assuntos
Ácido Aspártico Endopeptidases/antagonistas & inibidores , Pepsina A/antagonistas & inibidores , Piperidinas/química , Animais , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Pepstatinas/química , Peptídeos/química , Ligação Proteica , Conformação Proteica , Espectrometria de Fluorescência , Especificidade por Substrato , Suínos , Fatores de Tempo
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