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Biosíntesis de ácido pipecólico por RapL, una lisina ciclodeaminasa codificada en el clúster de genes de rapamicina
Gregory J Gatto1, Michael T Boyne, Neil L Kelleher
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Journal of the American Chemical Society
|March 16, 2006
Resumen
Este estudio valida la enzima RapL.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biosíntesis de Productos Naturales de Productos Naturales
- Enzimología Enzimología.
Sus antecedentes:
- La rapamicina, el FK506 y el FK520 son inmunosupresores cruciales.
- Estos productos naturales de macrolactona contienen un residuo de ácido pipecólico.
- El ácido pipecólico es biosintetizado a través de la ciclodeaminación de lisina.
Objetivo del estudio:
- Para investigar la función de la enzima RapL en la biosíntesis del ácido pipecólico.
- Para caracterizar el mecanismo catalítico de la ciclodeaminación de lisina.
- Proporcionar la primera caracterización in vitro de una lisina ciclodeaminasa.
Principales métodos:
- Sobreexpresión heteróloga y purificación de la enzima RapL.
- Ensayos enzimáticos utilizando L-lisina y L-ornitina como sustratos.
- Sustratos etiquetados isotópicamente para confirmar los detalles mecánicos.
- Análisis espectroscópico para determinar los requisitos de los cofactores.
Principales resultados:
- RapL convierte con éxito la L-lisina en ácido L-pipecólico a través de la ciclodeaminación.
- La reacción incluye catálisis redox con dinucleótido de nicotinamida adenina (NAD+).
- RapL exhibe una menor eficiencia con la L-ornitina y requiere NAD+ para una actividad óptima.
- Los estudios mecanicistas confirmaron la pérdida de aminas y la retención de hidrógeno en el carbono alfa.
Conclusiones:
- RapL es una enzima clave en la biosíntesis de importantes inmunosupresores.
- Este trabajo aclara el mecanismo de la ciclodeaminación de lisina.
- El estudio pone de relieve el papel del NAD+ en esta transformación enzimática única.
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