Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
J Mol Biol ; 434(22): 167844, 2022 11 30.
Artículo en Inglés | MEDLINE | ID: mdl-36181774

RESUMEN

Autoinhibition of p53 binding to MDMX requires two short-linear motifs (SLiMs) containing adjacent tryptophan (WW) and tryptophan-phenylalanine (WF) residues. NMR spectroscopy was used to show the WW and WF motifs directly compete for the p53 binding site on MDMX and circular dichroism spectroscopy was used to show the WW motif becomes helical when it is bound to the p53 binding domain (p53BD) of MDMX. Binding studies using isothermal titration calorimetry showed the WW motif is a stronger inhibitor of p53 binding than the WF motif when they are both tethered to p53BD by the natural disordered linker. We also investigated how the WW and WF motifs interact with the DNA binding domain (DBD) of p53. Both motifs bind independently to similar sites on DBD that overlap the DNA binding site. Taken together our work defines a model for complex formation between MDMX and p53 where a pair of disordered SLiMs bind overlapping sites on both proteins.


Asunto(s)
Proteínas Proto-Oncogénicas c-mdm2 , Proteína p53 Supresora de Tumor , Fenilalanina/química , Unión Proteica , Proteínas Proto-Oncogénicas c-mdm2/química , Triptófano/química , Proteína p53 Supresora de Tumor/química , Secuencias de Aminoácidos , Dominios Proteicos , Humanos
2.
Biomolecules ; 9(3)2019 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-30832340

RESUMEN

The disordered p53 transactivation domain (p53TAD) contains specific levels of transient helical secondary structure that are necessary for its binding to the negative regulators, mouse double minute 2 (Mdm2) and MdmX. The interactions of p53 with Mdm2 and MdmX are also modulated by posttranslational modifications (PTMs) of p53TAD including phosphorylation at S15, T18 and S20 that inhibits p53-Mdm2 binding. It is unclear whether the levels of transient secondary structure in p53TAD are changed by phosphorylation or other PTMs. We used phosphomimetic mutants to determine if adding a negative charge at positions 15 and 18 has any effect on the transient secondary structure of p53TAD and protein-protein binding. Using a combination of biophysical and structural methods, we investigated the effects of single and multisite phosphomimetics on the transient secondary structure of p53TAD and its interaction with Mdm2, MdmX, and the KIX domain. The phosphomimetics reduced Mdm2 and MdmX binding affinity by 3⁻5-fold, but resulted in minimal changes in transient secondary structure, suggesting that the destabilizing effect of phosphorylation on the p53TAD-Mdm2 interaction is primarily electrostatic. Phosphomimetics had no effect on the p53-KIX interaction, suggesting that increased binding of phosphorylated p53 to KIX may be influenced by decreased competition with its negative regulators.


Asunto(s)
Imitación Molecular , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Proteína p53 Supresora de Tumor/química , Proteína p53 Supresora de Tumor/metabolismo , Animales , Sitios de Unión , Humanos , Ratones , Oxidación-Reducción , Fosforilación , Estructura Secundaria de Proteína , Proteínas Proto-Oncogénicas c-mdm2/genética , Electricidad Estática
3.
Ann Allergy Asthma Immunol ; 99(6): 540-8, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18219836

RESUMEN

BACKGROUND: Previous studies have raised concerns regarding the safety of regular use of beta2-agonists for treating asthma. Few studies have explored the safety of at least 1 year of use of racemic albuterol, and none have examined long-term dosing of levalbuterol. OBJECTIVE: To examine the long-term safety of levalbuterol hydrofluoroalkane (HFA) vs racemic albuterol HFA administered via metered-dose inhaler (MDI) in patients with stable asthma. METHODS: Patients with mild to moderate asthma (mean forced expiratory volume in 1 second [FEVI], 68.3% of predicted) 12 years or older participated in a multicenter, parallel-group, open-label study. Patients were randomized to levalbuterol HFA MDI (90 microg; 2 actuations of 45 microg; n = 496) or racemic albuterol HFA MDI (180 microg; 2 actuations of 90 microg; n = 250) for 52 weeks of 4 times daily dosing. The primary end point was the incidence of postrandomization adverse events. Asthma exacerbations and pulmonary parameters were also assessed. RESULTS: The overall incidence of adverse events was similar for levalbuterol (72.0%) and racemic albuterol (76.8%). Rates of beta-mediated adverse events, serious adverse events, and discontinuations because of adverse events were low (<15%) and were comparable between groups. Rates of asthma adverse events for levalbuterol and racemic albuterol were 18.3% and 19.6%, respectively. Mean percentage of predicted FEV1 improved after dosing and was stable for both groups. CONCLUSION: In this trial, up to 52 weeks of regular use of levalbuterol HFA MDI or racemic albuterol HFA MDI was well tolerated, and no deterioration of lung function was detected during the study period.


Asunto(s)
Agonistas Adrenérgicos beta/administración & dosificación , Albuterol/administración & dosificación , Asma/tratamiento farmacológico , Inhaladores de Dosis Medida , Administración por Inhalación , Adolescente , Agonistas Adrenérgicos beta/efectos adversos , Adulto , Albuterol/efectos adversos , Asma/fisiopatología , Niño , Femenino , Volumen Espiratorio Forzado/efectos de los fármacos , Humanos , Masculino
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...