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Estructuras de las acetohidroxiacidas de hongos y plantas

Thierry Lonhienne¹, Yu Shang Low², Mario D Garcia²

¹School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia. t.lonhienne@uq.edu.au.

|July 9, 2020

Resumen

Las estructuras enzimáticas de la acetohidroxiacida sintasa (AHAS) revelan una arquitectura cruzada maltesa conservada. Este hallazgo aclara cómo se regula la biosíntesis de aminoácidos de cadena ramificada y cómo los herbicidas se dirigen a AHAS.

Área de la Ciencia:

La bioquímica
Enzimología
Biología estructural

Sus antecedentes:

La acetohidroxiacida sintasa (AHAS), o acetolactato sintasa, es crucial para la biosíntesis de aminoácidos de cadena ramificada.
AHAS es un objetivo validado para más de 50 herbicidas comerciales.
La enzima requiere subunidades catalíticas y reguladoras para una función óptima.

Objetivo del estudio:

Para aclarar la organización estructural de los complejos AHAS.
Comprender la comunicación entre las subunidades catalítica y reguladora.
Para investigar la conservación de la arquitectura AHAS en diferentes reinos.

Principales métodos:

Se utilizó la cristalografía de rayos X para determinar las estructuras de los complejos AHAS de Saccharomyces cerevisiae y Arabidopsis thaliana.
Se realizó un análisis estructural comparativo del complejo Mycobacterium tuberculosis AHAS.

Principales resultados:

Las subunidades reguladoras forman un núcleo, con dímeros de subunidad catalítica unidos, creando una forma de cruz maltesa.
Las ideas estructurales revelan vías para la activación de enzimas y la inhibición de la retroalimentación por aminoácidos de cadena ramificada.
El complejo AHAS de Mycobacterium tuberculosis comparte una arquitectura similar, lo que indica una conservación evolutiva.

Conclusiones:

La arquitectura cruzada maltesa conservada de AHAS es fundamental para su función en la biosíntesis de aminoácidos de cadena ramificada.
Comprender esta estructura proporciona una base para el diseño de herbicidas y el manejo de la resistencia.
La conservación estructural destaca la importancia evolutiva de este complejo enzimático.

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