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1.
J Org Chem ; 89(2): 1310-1314, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38170997

RESUMO

We report an efficient route for the synthesis of highly substituted 1-aminonaphthalenes from benzaldehydes. The method employs a stereoselective Still-Gennari modification of the Horner-Wadsworth-Emmons olefination to afford (E)-benzylidenesuccinonitrile precursors, which undergo Bronsted acid mediated benzannulation to afford 1-aminonaphthalene derivatives in 35-95% yield. The abundance of commercially available benzaldehydes, coupled with the simplicity of our method, enables many previously unexplored naphthalene substitution patterns to become readily accessible.

2.
J Am Chem Soc ; 144(22): 9610-9617, 2022 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-35613436

RESUMO

Aberrant tumor necrosis factor-α (TNFα) signaling is associated with many inflammatory diseases. The homotrimeric quaternary structure of TNFα is essential for receptor recognition and signal transduction. Previously, we described an engineered α/ß-peptide inhibitor that potently suppresses TNFα activity and resists proteolysis. Here, we present structural evidence that both the α/ß-peptide inhibitor and an all-α analogue bind to a monomeric form of TNFα. Calorimetry data support a 1:1 inhibitor/TNFα stoichiometry in solution. In contrast, previous cocrystal structures involving peptide or small-molecule inhibitors have shown the antagonists engaging a TNFα dimer. The structural data reveal why our inhibitors favor monomeric TNFα. Previous efforts to block TNFα-induced cell death with peptide inhibitors revealed that surfactant additives to the assay conditions cause a more rapid manifestation of inhibitory activity than is observed in the absence of additives. We attributed this effect to a loose surfactant TNFα association that lowers the barrier to trimer dissociation. Here, we used the new structural data to design peptide inhibitors bearing a surfactant-inspired appendage intended to facilitate TNFα trimer dissociation. The appendage modified the time course of protection from cell death.


Assuntos
Inibidores de Proteases , Fator de Necrose Tumoral alfa , Peptídeo Hidrolases/metabolismo , Peptídeos/farmacologia , Inibidores de Proteases/farmacologia , Transdução de Sinais , Tensoativos/farmacologia , Fator de Necrose Tumoral alfa/metabolismo
3.
J Am Chem Soc ; 143(15): 5958-5966, 2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33825470

RESUMO

The lower respiratory tract infections affecting children worldwide are in large part caused by the parainfluenza viruses (HPIVs), particularly HPIV3, along with human metapneumovirus and respiratory syncytial virus, enveloped negative-strand RNA viruses. There are no vaccines for these important human pathogens, and existing treatments have limited or no efficacy. Infection by HPIV is initiated by viral glycoprotein-mediated fusion between viral and host cell membranes. A viral fusion protein (F), once activated in proximity to a target cell, undergoes a series of conformational changes that first extend the trimer subunits to allow insertion of the hydrophobic domains into the target cell membrane and then refold the trimer into a stable postfusion state, driving the merger of the viral and host cell membranes. Lipopeptides derived from the C-terminal heptad repeat (HRC) domain of HPIV3 F inhibit infection by interfering with the structural transitions of the trimeric F assembly. Clinical application of this strategy, however, requires improving the in vivo stability of antiviral peptides. We show that the HRC peptide backbone can be modified via partial replacement of α-amino acid residues with ß-amino acid residues to generate α/ß-peptides that retain antiviral activity but are poor protease substrates. Relative to a conventional α-lipopeptide, our best α/ß-lipopeptide exhibits improved persistence in vivo and improved anti-HPIV3 antiviral activity in animals.


Assuntos
Lipopeptídeos/farmacologia , Vírus da Parainfluenza 3 Humana/efeitos dos fármacos , Infecções Respiratórias/patologia , Sequência de Aminoácidos , Aminoácidos/química , Aminoácidos/metabolismo , Animais , Antivirais/química , Antivirais/metabolismo , Antivirais/farmacologia , Linhagem Celular , Colesterol/química , Desenho de Fármacos , Humanos , Lipopeptídeos/química , Lipopeptídeos/metabolismo , Vírus da Parainfluenza 3 Humana/isolamento & purificação , Multimerização Proteica , Ratos , Infecções Respiratórias/virologia , Distribuição Tecidual , Temperatura de Transição , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/genética , Proteínas Virais de Fusão/metabolismo , Internalização do Vírus/efeitos dos fármacos
4.
J Am Chem Soc ; 142(5): 2140-2144, 2020 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-31951396

RESUMO

Human parainfluenza virus 3 (HPIV3) and respiratory syncytial virus (RSV) are leading causes of lower respiratory tract infections. There are currently no vaccines or antiviral therapeutics to treat HPIV3 or RSV infections. We recently reported a peptide (VIQKI), derived from the C-terminal heptad repeat (HRC) domain of the HPIV3 fusion (F) glycoprotein that inhibits infection by both HPIV3 and RSV. The dual inhibitory activity of VIQKI is due to its unique ability to bind to the N-terminal heptad repeat (HRN) domains of both HPIV3 and RSV F, thereby preventing the native HRN-HRC interactions required for viral entry. Here we describe the structure-guided design of dual inhibitors of HPIV3 and RSV fusion with improved efficacy. We show that VIQKI derivatives possessing one (I456F) or two (I454F/I456F) phenylalanine substitutions near the N-terminus exhibit more stable assemblies with the RSV-HRN domain and enhanced antiviral efficacy against both HPIV3 and RSV infection. Cocrystal structures of the new Phe-substituted inhibitors coassembled with HPIV3 or RSV-HRN domains reveal that the I456F substitution makes intimate hydrophobic contact with the core trimers of both HPIV3 and RSV F.


Assuntos
Antivirais/farmacologia , Oligopeptídeos/farmacologia , Vírus da Parainfluenza 3 Humana/efeitos dos fármacos , Vírus Sincicial Respiratório Humano/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos , Sequência de Aminoácidos , Antivirais/química , Cristalografia por Raios X , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Oligopeptídeos/química , Vírus da Parainfluenza 3 Humana/fisiologia , Conformação Proteica , Vírus Sincicial Respiratório Humano/fisiologia
5.
J Am Chem Soc ; 141(32): 12648-12656, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31268705

RESUMO

Human parainfluenza virus 3 (HPIV3) and respiratory syncytial virus (RSV) cause lower respiratory infection in infants and young children. There are no vaccines for these pathogens, and existing treatments have limited or questionable efficacy. Infection by HPIV3 or RSV requires fusion of the viral and cell membranes, a process mediated by a trimeric fusion glycoprotein (F) displayed on the viral envelope. Once triggered, the pre-fusion form of F undergoes a series of conformational changes that first extend the molecule to allow for insertion of the hydrophobic fusion peptide into the target cell membrane and then refold the trimeric assembly into an energetically stable post-fusion state, a process that drives the merger of the viral and host cell membranes. Peptides derived from defined regions of HPIV3 F inhibit infection by HPIV3 by interfering with the structural transitions of the trimeric F assembly. Here we describe lipopeptides derived from the C-terminal heptad repeat (HRC) domain of HPIV3 F that potently inhibit infection by both HPIV3 and RSV. The lead peptide inhibits RSV infection as effectively as does a peptide corresponding to the RSV HRC domain itself. We show that the inhibitors bind to the N-terminal heptad repeat (HRN) domains of both HPIV3 and RSV F with high affinity. Co-crystal structures of inhibitors bound to the HRN domains of HPIV3 or RSV F reveal remarkably different modes of binding in the N-terminal segment of the inhibitor.


Assuntos
Lipopeptídeos/farmacologia , Vírus da Parainfluenza 3 Humana/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Inibidores de Proteínas Virais de Fusão/farmacologia , Proteínas Virais de Fusão/farmacologia , Sequência de Aminoácidos , Cristalografia por Raios X , Humanos , Lipopeptídeos/metabolismo , Testes de Sensibilidade Microbiana , Vírus da Parainfluenza 3 Humana/química , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Mucosa Respiratória/virologia , Vírus Sinciciais Respiratórios/química , Inibidores de Proteínas Virais de Fusão/metabolismo , Proteínas Virais de Fusão/metabolismo , Internalização do Vírus/efeitos dos fármacos
6.
Chemistry ; 22(43): 15212-15215, 2016 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-27549912

RESUMO

Fluorescent-sensor design requires consideration of how photochemical dynamics control properties of a sensing state. Transient absorption (TA) spectroscopy reveals an ultrafast net [1,3]-hydrogen shift following excitation of a protonated methoxy benzoindolizine (bzi) sensor in solution. These photochemical dynamics explain a quenched pH-responsive fluorescence shift and dramatically reduced fluorescence quantum yield relative to other (e. g. methyl) bzi compounds that do not tautomerize. Calculations predict the energetic and structural feasibility for rearrangement in protonated bzi compounds, such that interaction between the pi-network and strongly electron-donating methoxyl must lower the barrier for suprafacial H or H+ shift across an allylic moiety. As bzi compounds broadly exhibit pH-responsive emission shifts, chemical interactions that modulate this electronic interaction and suppress tautomerization could be used to facilitate binding- or surface-specific acid-responsive sensing.

7.
Res Sq ; 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39070635

RESUMO

Disulfide bonds provide a convenient method for chemoselective alteration of peptide and protein structure and function. We previously reported that mild oxidation of a p53-derived bisthiol peptide (CTFANLWRLLAQNC) under dilute non-denaturing conditions led to unexpected disulfide-linked dimers as the exclusive product. The dimers were antiparallel, significantly α-helical, resistant to protease degradation, and easily reduced back to the original bisthiol peptide. Here we examine the intrinsic factors influencing peptide dimerization using a combination of amino acid substitution, circular dichroism (CD) spectroscopy, and X-ray crystallography. CD analysis of peptide variants suggests critical roles for Leu6 and Leu10 in the formation of stable disulfide-linked dimers. The 1.0 Å resolution crystal structure of the peptide dimer supports these data, revealing a leucine-rich LxxLL dimer interface with canonical knobs-into-holes packing. Two levels of higher-order oligomerization are also observed in the crystal: an antiparallel "dimer of dimers" mediated by Phe3 and Trp7 residues in the asymmetric unit and a tetramer of dimers mediated by Trp7 and Leu10. In CD spectra of Trp-containing peptide variants, minima at 227 nm provide evidence for the dimer of dimers in dilute aqueous solution. Importantly, and in contrast to the original dimer model, the canonical leucine-rich core and robust dimerization of most peptide variants suggests a tunable molecular architecture to target various proteins and evaluate how folding and oligomerization impact various properties, such as cell permeability.

8.
ACS Infect Dis ; 6(8): 2017-2022, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32692914

RESUMO

Partial replacement of α-amino acid residues with ß-amino acid residues has been established as a strategy for preserving target-engagement by helix-forming polypeptides while altering other properties. The impact of ß-residue incorporation within polypeptides that adopt less regular conformations, however, has received less attention. The C-terminal heptad repeat (HRC) domains of fusion glycoproteins from pathogenic paramyxoviruses contain a segment that must adopt an extended conformation in order to coassemble with the N-terminal heptad repeat (HRN) domain in the postfusion state and drive a merger of the viral envelope with a target cell membrane. Here, we examine the impact of single α-to-ß substitutions within this extended N-terminal segment of an engineered HRC peptide designated VIQKI. Stabilities of hexameric coassemblies formed with the native human parainfluenza virus 3 (HPIV3) HRN have been evaluated, the structures of five coassemblies have been determined, and antiviral efficacies have been measured. Many sites within the extended segment show functional tolerance of α-to-ß substitution. These results offer a basis for future development of paramyxovirus infection inhibitors with novel biological activity profiles, possibly including resistance to proteolysis.


Assuntos
Proteínas Virais de Fusão , Internalização do Vírus , Antivirais/farmacologia , Humanos , Vírus da Parainfluenza 3 Humana , Peptídeos , Proteínas Virais de Fusão/genética
9.
mBio ; 11(5)2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33082259

RESUMO

The emergence of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the etiological agent of the 2019 coronavirus disease (COVID-19), has erupted into a global pandemic that has led to tens of millions of infections and hundreds of thousands of deaths worldwide. The development of therapeutics to treat infection or as prophylactics to halt viral transmission and spread is urgently needed. SARS-CoV-2 relies on structural rearrangements within a spike (S) glycoprotein to mediate fusion of the viral and host cell membranes. Here, we describe the development of a lipopeptide that is derived from the C-terminal heptad repeat (HRC) domain of SARS-CoV-2 S that potently inhibits infection by SARS-CoV-2. The lipopeptide inhibits cell-cell fusion mediated by SARS-CoV-2 S and blocks infection by live SARS-CoV-2 in Vero E6 cell monolayers more effectively than previously described lipopeptides. The SARS-CoV-2 lipopeptide exhibits broad-spectrum activity by inhibiting cell-cell fusion mediated by SARS-CoV-1 and Middle East respiratory syndrome coronavirus (MERS-CoV) and blocking infection by live MERS-CoV in cell monolayers. We also show that the SARS-CoV-2 HRC-derived lipopeptide potently blocks the spread of SARS-CoV-2 in human airway epithelial (HAE) cultures, an ex vivo model designed to mimic respiratory viral propagation in humans. While viral spread of SARS-CoV-2 infection was widespread in untreated airways, those treated with SARS-CoV-2 HRC lipopeptide showed no detectable evidence of viral spread. These data provide a framework for the development of peptide therapeutics for the treatment of or prophylaxis against SARS-CoV-2 as well as other coronaviruses.IMPORTANCE SARS-CoV-2, the causative agent of COVID-19, continues to spread globally, placing strain on health care systems and resulting in rapidly increasing numbers of cases and mortalities. Despite the growing need for medical intervention, no FDA-approved vaccines are yet available, and treatment has been limited to supportive therapy for the alleviation of symptoms. Entry inhibitors could fill the important role of preventing initial infection and preventing spread. Here, we describe the design, synthesis, and evaluation of a lipopeptide that is derived from the HRC domain of the SARS-CoV-2 S glycoprotein that potently inhibits fusion mediated by SARS-CoV-2 S glycoprotein and blocks infection by live SARS-CoV-2 in both cell monolayers (in vitro) and human airway tissues (ex vivo). Our results highlight the SARS-CoV-2 HRC-derived lipopeptide as a promising therapeutic candidate for SARS-CoV-2 infections.


Assuntos
Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Lipopeptídeos/farmacologia , Glicoproteína da Espícula de Coronavírus/química , Internalização do Vírus/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antivirais/química , Betacoronavirus/química , Betacoronavirus/fisiologia , COVID-19 , Chlorocebus aethiops , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Células HEK293 , Humanos , Lipopeptídeos/química , Fusão de Membrana/efeitos dos fármacos , Coronavírus da Síndrome Respiratória do Oriente Médio/química , Coronavírus da Síndrome Respiratória do Oriente Médio/efeitos dos fármacos , Coronavírus da Síndrome Respiratória do Oriente Médio/fisiologia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão , Domínios Proteicos , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/virologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/química , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/efeitos dos fármacos , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/fisiologia , SARS-CoV-2 , Células Vero
10.
RSC Adv ; 6(66): 61249-61253, 2016 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-28580137

RESUMO

6-Amino-8-cyanobenzo[1, 2-b]indolizines, a new class of photoluminescent materials, exhibit reversible pH-dependent optical properties characterized by an uncommon and dramatic blue shift in fluorescence emission when protonated. Acid titration and NMR spectroscopy experiments reveal that, rather than the anticipated N-protonation, C-protonation and loss of aromaticity is responsible for the observed photophysical changes. Efficient synthesis from indole-2-carboxaldehydes makes variously substituted versions of this nucleus readily available to tune optical and pH effects.

11.
Org Lett ; 17(8): 1822-5, 2015 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-25815402

RESUMO

An efficient route to substituted N-fused aromatic heterocycles, including indolizines, imidazo[1,2-a]pyridines, and imidazo[1,5-a]pyridines from azole aldehydes, is reported. Wittig olefination of the aldehydes with fumaronitrile and triethylphosphine affords predominantly E-alkenes that undergo rapid cyclization upon treatment with a mild base. Substituent control of the 1-, 2-, and 3-positions of the resulting heteroaromatic bicycles is shown. Alternatively, the isolable E-alkene undergoes selective alkylation with electrophiles, followed by in situ annulation to indolizines additionally substituted at the 6-position.


Assuntos
Indolizinas/síntese química , Piridinas/síntese química , Indolizinas/química , Estrutura Molecular , Piridinas/química , Estereoisomerismo
12.
Org Lett ; 16(24): 6334-7, 2014 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-25479249

RESUMO

Among privileged structures, indoles occupy a central place in medicinal chemistry and alkaloid research. Here we report a flexible and efficient conversion of pyrrole-3-carboxaldehydes to substituted 7-amino-5-cyanoindoles. Phosphine addition to fumaronitrile proceeds with prototropic rearrangement of the initially formed zwitterion to the thermodynamically favored phosphonium ylide, which is poised for in situ Wittig olefination. The predominantly E-alkene product positions the allylic nitrile for facile intramolecular Hoeben-Hoesch reaction in the presence of BF3·OEt2. Syntheses of 2,5- and 3,5-disubstituted 7-aminoindoles are illustrated. Additionally, dianion alkylation of the allylic nitrile is demonstrated to furnish, after cyclization, 5,6-disubstituted 7-aminoindoles to further exemplify this scalable and high-yielding method.


Assuntos
Indóis/síntese química , Nitrilas/química , Pirróis/química , Alquilação , Catálise , Ciclização , Indóis/química , Estrutura Molecular , Estereoisomerismo
13.
Medchemcomm ; 5(6): 826-830, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25068033

RESUMO

Despite a rising demand for anti-obesity therapeutics, few effective pharmacological options are clinically available that target the synthesis and accumulation of body fat. Moderate inhibition of mammalian glycerol-3-phosphate acyltransferase (GPAT) with 2-(alkanesulfonamido)benzoic acids has recently been described in vitro, accompanied by promising weight loss in vivo. In silico docking studies with 2-(octanesulfonamido)benzoic acid modeled into the active site of squash GPAT revealed an unoccupied volume lined with hydrophobic residues proximal to C-4 and C-5 of the benzoic acid ring. In an effort to produce more potent GPAT inhibitors, a series of 4- and 5-substituted analogs were designed, synthesized, and evaluated for inhibitory activity. In general, compounds containing hydrophobic substituents at the 4- and 5-positions, such as biphenyl and alkylphenyl hydrocarbons, exhibited an improved inhibitory activity against GPAT in vitro. The most active compound, 4-([1,1'-biphenyl]-4-carbonyl)-2-(octanesulfonamido)benzoic acid, demonstrated an IC50 of 8.5 µM and represents the best GPAT inhibitor discovered to date. Conversely, further substitution with hydroxyl or fluoro groups, led to a 3-fold decrease in activity. These results are consistent with the presence of a hydrophobic pocket and may support the binding model as a potential tool for developing more potent inhibitors.

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