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Bases moleculares de la absorción de nitratos por el transportador de nitratos de las plantas NRT1.1
Joanne L Parker1, Simon Newstead2
1Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
Nature
|February 28, 2014
Resumen
La Arabidopsis thaliana NRT1.1 es una especie de la familia Arabidopsis.
Área de la Ciencia:
- Biología vegetal Biología vegetal
- Biología molecular y celular Biología molecular y celular
- La bioquímica es la bioquímica.
Sus antecedentes:
- La familia NRT1 / PTR facilita la asimilación de nitrógeno a través de la captación de péptidos en eucariotas y bacterias.
- En las plantas, los transportadores NRT1/PTR se han diversificado para transportar nitrato, hormonas y metabolitos secundarios.
- El transportador de nitratos vegetales 1.1 (NRT1.1) cambia entre estados de baja y alta afinidad en la fosforilación en respuesta a los niveles de nitratos.
Objetivo del estudio:
- Para aclarar la base estructural de la unión y el transporte de nitratos por Arabidopsis thaliana NRT1.1.1.
- Comprender el mecanismo por el cual la fosforilación regula la actividad de NRT1.1.
- Explorar la divergencia evolutiva de la familia NRT1/PTR en el reconocimiento de ligandos.
Principales métodos:
- Cristalografía de rayos X para determinar las estructuras apo y ligadas al nitrato de Arabidopsis thaliana NRT1.1.1.
- Ensayos de unión in vitro para evaluar la interacción con los nitratos.
- Análisis de transporte para cuantificar la actividad del transportador.
Principales resultados:
- Las estructuras cristalinas revelan el sitio de unión para el nitrato, destacando el papel crucial de la histidina 356.
- Se propone la fosforilación para mejorar la flexibilidad estructural, aumentando así las tasas de transporte.
- Las comparaciones estructurales iluminan la evolución del reconocimiento de diversos ligandos nitrogenados dentro de la familia NRT1/PTR.
Conclusiones:
- La histidina 356 es crítica para la unión de nitratos en la Arabidopsis thaliana NRT1.1.1.
- Los cambios estructurales inducidos por la fosforilación regulan la afinidad y la velocidad de transporte de NRT1.1.
- La familia NRT1/PTR exhibe mecanismos de transporte de nutrientes conservados junto con una especificidad de ligando evolucionada.
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