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Se produce un intermediario ciclico [2.1.0]-fusionado durante la biosíntesis de nucleósidos de oxetano

Yu-Hsuan Lee¹, Po-Hsun Fan¹, Yu-Cheng Yeh¹

¹Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.

Journal of the American Chemical Society

|July 11, 2025

Resumen

Los investigadores aclararon la biosíntesis de los nucleósidos de oxetano, revelando cómo las enzimas dependientes de B12 AlsB y OxsB forman intermedios bicíclicos tensos. Estos intermediarios se convierten luego en albucidina y oxetanocina A por AlsA y OxsA, completando las vías.

Área de la Ciencia:

La bioquímica
Enzimología
Biosíntesis de nucleósidos

Sus antecedentes:

AlsB y OxsB son enzimas homólogas dependientes de la B12.
Están involucrados en la síntesis de nucleósidos de oxetano como la albucidina y la oxetanocina A.
Se requiere AlsA y OxsA para completar la formación del anillo de oxetano.

Objetivo del estudio:

Elucidar las vías biosintéticas completas de la oxetanocina A y la albucidina.
Caracterizar los mecanismos catalíticos del AlsB y del OxsB.
Para entender el papel de la cobalamina en la estabilización radical.

Principales métodos:

Ensayos enzimáticos con el uso de 5'-fosfatos de 2'-deoxyadenosina.
Caracterización de los intermediarios de la reacción.
Análisis de las funciones de los cofactores en la química radical.

Principales resultados:

AlsB y OxsB catalizan la formación de enlaces C-C intramoleculares para crear un intermediario ciclico tensado.
Este intermediario se convierte en fosfato de oxetanocina A o fosfato de albucidina por OxsA o AlsA.
La vía implica la abstracción de átomos de hidrógeno y la recombinación radical facilitada por la cobalamina.

Conclusiones:

El estudio completa la descripción de las vías de biosíntesis de la oxetanocina A y de la albucidina.
La cobalamina juega un papel sin precedentes en la estabilización de los radicales de carbono intermedios.
Este trabajo revela un nuevo mecanismo para la recombinación radical intramolecular en la síntesis enzimática.

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