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1.
J Biosci Bioeng ; 138(2): 127-136, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38851988

RESUMO

Respiratory syncytial virus (RSV) infection is an acute respiratory infection caused by RSV. It occurs worldwide, and for over 50 years, several attempts have been made to research and develop vaccines to prevent RSV infection; effective preventive vaccines are eagerly awaited. The RSV fusion (F) protein, which has gained attention as a vaccine antigen, causes a dynamic structural change from the preF to postF state. Therefore, the structural changes in proteins must be regulated to produce a vaccine antigen that can efficiently induce antibodies with high virus-neutralizing activity. We successfully discovered several mutations that stabilized the antigen site Ø in the preF state, trimerized it, and improved the level of protein expression through observation and computational analysis of the RSV-F protein structure and amino acid mutation analysis of RSV strains. The four RSV-F protein mutants that resulted from the combination of these effective mutations stably conserved a wide range of preF- and trimeric preF-specific epitopes with high virus-neutralizing activity. Absorption assay using human serum revealed that mutants constructed bound to antibodies with virus-neutralizing activity that were induced by natural RSV infection, whereas they hardly bound to anti-postF antibodies without virus-neutralizing activity. Furthermore, mouse immunization demonstrated that our constructed mutants induced a high percentage of antibodies that bind to the preF-specific antigen site. These characteristics suggest that the mutants constructed can be superior vaccine antigens from the viewpoint of RSV infection prevention effect and safety.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Antígenos Virais , Infecções por Vírus Respiratório Sincicial , Vacinas contra Vírus Sincicial Respiratório , Proteínas Virais de Fusão , Animais , Humanos , Proteínas Virais de Fusão/imunologia , Proteínas Virais de Fusão/genética , Vacinas contra Vírus Sincicial Respiratório/imunologia , Vacinas contra Vírus Sincicial Respiratório/genética , Vacinas contra Vírus Sincicial Respiratório/administração & dosagem , Camundongos , Anticorpos Antivirais/imunologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Infecções por Vírus Respiratório Sincicial/imunologia , Anticorpos Neutralizantes/imunologia , Antígenos Virais/imunologia , Antígenos Virais/genética , Mutação , Epitopos/imunologia , Epitopos/genética , Vírus Sincicial Respiratório Humano/imunologia , Vírus Sincicial Respiratório Humano/genética , Camundongos Endogâmicos BALB C , Vírus Sinciciais Respiratórios/imunologia , Vírus Sinciciais Respiratórios/genética
2.
Nat Struct Mol Biol ; 31(1): 159-169, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38057552

RESUMO

Sodium-glucose cotransporter 2 (SGLT2) is imporant in glucose reabsorption. SGLT2 inhibitors suppress renal glucose reabsorption, therefore reducing blood glucose levels in patients with type 2 diabetes. We and others have developed several SGLT2 inhibitors starting from phlorizin, a natural product. Using cryo-electron microscopy, we present the structures of human (h)SGLT2-MAP17 complexed with five natural or synthetic inhibitors. The four synthetic inhibitors (including canagliflozin) bind the transporter in the outward conformations, while phlorizin binds it in the inward conformation. The phlorizin-hSGLT2 interaction exhibits biphasic kinetics, suggesting that phlorizin alternately binds to the extracellular and intracellular sides. The Na+-bound outward-facing and unbound inward-open structures of hSGLT2-MAP17 suggest that the MAP17-associated bundle domain functions as a scaffold, with the hash domain rotating around the Na+-binding site. Thus, Na+ binding stabilizes the outward-facing conformation, and its release promotes state transition to inward-open conformation, exhibiting a role of Na+ in symport mechanism. These results provide structural evidence for the Na+-coupled alternating-access mechanism proposed for the transporter family.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Transportador 2 de Glucose-Sódio/metabolismo , Proteínas Facilitadoras de Transporte de Glucose , Florizina/farmacologia , Florizina/química , Florizina/metabolismo , Microscopia Crioeletrônica , Glucose/metabolismo
3.
Nano Lett ; 22(3): 904-910, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35044773

RESUMO

Graphene quantum dots (GQDs) are quasi-zero-dimensional, carbon-based luminescent nanomaterials that possess desirable physical properties, such as high photostability, low cytotoxicity, good biocompatibility, and excellent water solubility; however, their long radiative lifetimes significantly limit their use in, e.g., light emitting devices where a fast spontaneous emission rate is essential. Despite a few reports on GQD fluorescence enhancements using metal nanostructures, studies of enhanced spontaneous emission rate remain outstanding. Here, we report fast and bright luminescence by coupling gap plasmon modes to nanoparticle emitters. Through precise control over the nanoparticle's local density of states (LDOS), we achieved a 220-fold increase in the PL intensity. The shortest radiative lifetime obtained was below 8.0 ps and limited by the instrument response, which is over 288-fold shorter than the lifetime of uncoupled GQDs. These findings may benefit the future development of rapid displays and open the possibility of constructing high-frequency classical or quantum telecommunication systems.


Assuntos
Grafite , Nanoestruturas , Pontos Quânticos , Carbono , Grafite/química , Luminescência , Pontos Quânticos/química
4.
Chemistry ; 22(40): 14213-8, 2016 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-27527513

RESUMO

A new class of ferroelectric coordination-based polymers has been developed by the self-assembly of lipophilic zinc porphyrin (ZnP) and ditopic bridging ligands. The ligands contain dipolar benzothiadiazole or fluorobenzene units, which are axially coordinated to ZnP with the dipole moments oriented perpendicular to the coordination axes. The coordination-based polymers show ferroelectric characteristics in the liquid crystalline state, as revealed by distinctive hysteresis in the polarization-electric field (P-E) loops and inversion current peaks in current-voltage (I-V) loops. The observed ferroelectric properties are explainable by flip-flop rotation of the dipolar axle ligands induced by the applied electric field, as demonstrated by the positive-up-negative-down (PUND) measurements. The present system provides a new operating principle in supramolecular ferroelectrics.

5.
Biochem Biophys Res Commun ; 434(2): 191-6, 2013 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-23501107

RESUMO

In recent years, various dipeptidyl peptidase IV (DPP-4) inhibitors have been released as therapeutic drugs for type 2 diabetes in many countries. In spite of their diverse chemical structures, no comparative studies of their binding modes in the active site of DPP-4 have been disclosed. We determined the co-crystal structure of vildagliptin with DPP-4 by X-ray crystallography and compared the binding modes of six launched inhibitors in DPP-4. The inhibitors were categorized into three classes on the basis of their binding subsites: (i) vildagliptin and saxagliptin (Class 1) form interactions with the core S1 and S2 subsites and a covalent bond with Ser630 in the catalytic triad; (ii) alogliptin and linagliptin (Class 2) form interactions with the S1' and/or S2' subsites in addition to the S1 and S2 subsites; and (iii) sitagliptin and teneligliptin (Class 3) form interactions with the S1, S2 and S2 extensive subsites. The present study revealed that the additional interactions with the S1', S2' or S2 extensive subsite may increase DPP-4 inhibition beyond the level afforded by the fundamental interactions with the S1 and S2 subsites and are more effective than forming a covalent bond with Ser630.


Assuntos
Adamantano/análogos & derivados , Domínio Catalítico , Dipeptidil Peptidase 4/química , Inibidores da Dipeptidil Peptidase IV/química , Nitrilas/química , Pirrolidinas/química , Adamantano/química , Cristalografia por Raios X , Dipeptídeos/química , Humanos , Complexos Multiproteicos/análise , Complexos Multiproteicos/química , Oligopeptídeos/química , Piperidinas/química , Ligação Proteica , Mapeamento de Interação de Proteínas , Pirazinas/química , Pirazóis/química , Serina/química , Fosfato de Sitagliptina , Relação Estrutura-Atividade , Tiazolidinas/química , Triazóis/química , Uracila/análogos & derivados , Uracila/química , Vildagliptina , Difração de Raios X
6.
Bioorg Med Chem ; 20(19): 5705-19, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22959556

RESUMO

Dipeptidyl peptidase IV (DPP-4) inhibition is suitable mechanism for once daily oral dosing regimen because of its low risk of hypoglycemia. We explored linked bicyclic heteroarylpiperazines substituted at the γ-position of the proline structure in the course of the investigation of l-prolylthiazolidines. The efforts led to the discovery of a highly potent, selective, long-lasting and orally active DPP-4 inhibitor, 3-[(2S,4S)-4-[4-(3-methyl-1-phenyl-1H-pyrazol-5-yl)piperazin-1-yl]pyrrolidin-2-ylcarbonyl]thiazolidine (8 g), which has a unique structure characterized by five consecutive rings. An X-ray co-crystal structure of 8 g in DPP-4 demonstrated that the key interaction between the phenyl ring on the pyrazole and the S(2) extensive subsite of DPP-4 not only boosted potency, but also increased selectivity. Compound 8 g, at 0.03 mg/kg or higher doses, significantly inhibited the increase of plasma glucose levels after an oral glucose load in Zucker fatty rats. Compound 8 g (teneligliptin) has been approved for the treatment of type 2 diabetes in Japan.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Inibidores da Dipeptidil Peptidase IV/química , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Pirazóis/química , Pirazóis/uso terapêutico , Tiazolidinas/química , Tiazolidinas/uso terapêutico , Animais , Glicemia/metabolismo , Cristalografia por Raios X , Diabetes Mellitus Tipo 2/enzimologia , Dipeptidil Peptidase 4/metabolismo , Inibidores da Dipeptidil Peptidase IV/farmacocinética , Inibidores da Dipeptidil Peptidase IV/farmacologia , Teste de Tolerância a Glucose , Haplorrinos , Humanos , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/farmacologia , Masculino , Simulação de Acoplamento Molecular , Pirazóis/farmacocinética , Pirazóis/farmacologia , Ratos , Ratos Wistar , Ratos Zucker , Tiazolidinas/farmacocinética , Tiazolidinas/farmacologia
7.
Bioorg Med Chem ; 20(16): 5033-41, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22824762

RESUMO

Hypoglycemic agents with a mechanism of depeptidyl peptidase IV (DPP-4) inhibition are suitable for once daily oral dosing. It is difficult to strike a balance between inhibitory activity and duration of action in plasma for inhibitors bearing an electrophilic nitrile group. We explored fused bicyclic heteroarylpiperazine substituted at the γ-position of the proline structure in the investigation of L-prolylthiazolidines lacking the electrophilic nitrile. Among them, 2-trifluoroquinolyl compound 8g is the most potent, long-lasting DPP-4 inhibitor (IC(50) = 0.37 nmol/L) with high selectivity against other related peptidases. X-ray crystal structure determination of 8g indicates that CH-π interactions generated between the quinolyl ring and the guanidinyl group of Arg358 enhances the DPP-4 inhibitory activity and selectivity.


Assuntos
Compostos Bicíclicos com Pontes/química , Dipeptidil Peptidase 4/metabolismo , Inibidores da Dipeptidil Peptidase IV/química , Inibidores da Dipeptidil Peptidase IV/farmacologia , Nitrilas/química , Piperazinas/química , Prolina/análogos & derivados , Prolina/síntese química , Prolina/farmacologia , Tiazolidinas/síntese química , Tiazolidinas/farmacologia , Animais , Cristalografia por Raios X , Dipeptidil Peptidase 4/sangue , Inibidores da Dipeptidil Peptidase IV/síntese química , Relação Dose-Resposta a Droga , Humanos , Masculino , Modelos Moleculares , Estrutura Molecular , Prolina/química , Ratos , Ratos Wistar , Relação Estrutura-Atividade , Tiazolidinas/química
8.
Biochemistry ; 45(3): 783-92, 2006 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-16411754

RESUMO

The crystal structure of penicillin binding protein 4 (PBP4) from Escherichia coli, which has both DD-endopeptidase and DD-carboxypeptidase activity, is presented. PBP4 is one of 12 penicillin binding proteins in E. coli involved in the synthesis and maintenance of the cell wall. The model contains a penicillin binding domain similar to known structures, but includes a large insertion which folds into domains with unique folds. The structures of the protein covalently attached to five different antibiotics presented here show the active site residues are unmoved compared to the apoprotein, but nearby surface loops and helices are displaced in some cases. The altered geometry of conserved active site residues compared with those of other PBPs suggests a possible cause for the slow deacylation rate of PBP4.


Assuntos
Antibacterianos/química , Antibacterianos/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Escherichia coli/química , Proteínas de Ligação às Penicilinas/química , Proteínas de Ligação às Penicilinas/metabolismo , D-Ala-D-Ala Carboxipeptidase Tipo Serina/química , D-Ala-D-Ala Carboxipeptidase Tipo Serina/metabolismo , Sequência de Aminoácidos , Cristalografia por Raios X , Modelos Moleculares , Dados de Sequência Molecular
9.
Acta Crystallogr D Biol Crystallogr ; 59(Pt 1): 23-31, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12499535

RESUMO

Precursors for isoprenoid synthesis are essential in all organisms. These compounds are synthesized by one of two known routes: the well characterized mevalonate pathway or a recently discovered non-mevalonate route which is used in many bacteria and human pathogens. Since the second pathway is both vital and unlike any found in humans, enzymes catalysing reactions along this synthetic route are possible drug targets. The structure of one such enzyme from the thermophilic bacterium Thermus thermophilus has been solved to high resolution in the presence of substrate and with a substrate analogue. Enzyme co-crystallized with substrate shows only one product, cytosine monophosphate (CMP), in the active site. At the high resolution of the refinement (1.6 A) the positions and coordination of the magnesium ions in the active site are clearly seen.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli , Fósforo-Oxigênio Liases/química , Fósforo-Oxigênio Liases/metabolismo , Fosfatos de Poli-Isoprenil/biossíntese , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Sítios de Ligação , Catálise , Cristalografia por Raios X , Monofosfato de Citidina/metabolismo , Lisina/metabolismo , Magnésio/química , Magnésio/metabolismo , Ácido Mevalônico/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Fósforo-Oxigênio Liases/genética , Fósforo-Oxigênio Liases/isolamento & purificação , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Thermus thermophilus/enzimologia
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