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Una inusual reacción de escisión de enlace carbono-carbono durante la biosíntesis de fosfinotricina
Robert M Cicchillo1, Houjin Zhang, Joshua A V Blodgett
1Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Nature
|June 12, 2009
Resumen
Los investigadores reconstituyeron una reacción enzimática sin precedentes, rompiendo un enlace fósforo-carbono en el 2-hidroxietilfosfonato (HEP) para formar hidroximetilfosfonato (HMP). Este descubrimiento amplía el conocimiento de las enzimas mononucleares de hierro no hemo y sus capacidades catalíticas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Química orgánica es la química orgánica.
Sus antecedentes:
- Los enlaces fósforo-carbono son cruciales en los productos naturales para la medicina y la agricultura.
- El tripeptido de fosfinotricina, que contiene fosfinotricina y alanina, es un componente clave en herbicidas como Basta y Liberty, utilizados con cultivos transgénicos.
- Estudios anteriores indicaron que el 2-hidroxietilfosfonato (HEP) se convierte en hidroximetilfosfonato (HMP) durante la biosíntesis del tripeptido de fosfinotricina.
Objetivo del estudio:
- Reconstituir y caracterizar la nueva reacción de escisión de enlace C(sp(3)) -C(sp(3)) que convierte HEP en HMP in vitro.
- Para aclarar la estructura y el mecanismo de la enzima responsable de esta transformación.
- Para expandir las reacciones conocidas catalizadas por la familia de enzimas de hierro no hemo mononucleares 2-His-1-carboxilato.
Principales métodos:
- In vitro reconstitución de la reacción enzimática.
- Cristalografía de rayos X para determinar la estructura de la enzima.
- Pruebas bioquímicas para analizar la actividad enzimática y los requisitos de cofactores.
Principales resultados:
- Se ha reconstituido con éxito la escisión de enlace in vitro C(sp(3)) -C(sp(3)) de HEP a HMP y formate.
- Determinación de la estructura cristalina de rayos X de la dioxigenasa dependiente de hierro no hemo mononuclear.
- Se demostró que el consumo oxidativo de HEP por parte de la enzima no requiere cofactores adicionales o electrones exógenos, a diferencia de la mayoría de las enzimas relacionadas.
Conclusiones:
- El estudio revela una conversión enzimática sin precedentes de HEP a HMP, expandiendo el conocido repertorio catalítico de enzimas de hierro mononucleares no hemo.
- Los hallazgos proporcionan información estructural y mecanicista sobre esta dioxigenasa única.
- Este trabajo contribuye a comprender la biosíntesis de la fosfinotricina y el campo más amplio de la química de los organofosforos.
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