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Estructura cristalina de la DMSO reductasa: cambios ligados al redox en la coordinación de la molibdopterina
H Schindelin1, C Kisker, J Hilton
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA.
Science (New York, N.Y.)
|June 14, 1996
Resumen
Se analizó estructuralmente la dimetilsulfóxido (DMSO) reductasa, crucial para la regulación del clima. Su cofactor de molibdeno muestra una coordinación distinta, revelando conocimientos sobre los mecanismos de reducción del sustrato.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Ciencias ambientales Ciencias ambientales.
Sus antecedentes:
- La dimetilsulfóxido (DMSO) reductasa es una molibdoenzima involucrada en la liberación de dimetilsulfuro, un gas que influye en el clima.
- El dimetilsulfuro juega un papel en la nucleación de nubes y la regulación del clima global.
- Comprender la estructura de la enzima es clave para dilucidar su mecanismo catalítico.
Objetivo del estudio:
- Para determinar la estructura cristalina de la DMSO reductasa de Rhodobacter sphaeroides. para determinar la estructura cristalina de DMSO reductasa de Rhodobacter sphaeroides. para determinar la estructura cristalina de DMSO reductasa de Rhodobacter sphaeroides. para determinar la estructura cristalina de DMSO reductasa de Rhodobacter sphaeroides. para determinar la estructura cristalina de DMSO reductasa de Rhodobacter sphaeroides. para determinar la estructura cristalina de DMSO reductasa de Rhodobacter sphaeroides. para determinar la estructura cristalina de DMSO reductasa de Rhodobacter sphaeroides.
- Para investigar la coordinación del cofactor de molibdeno en diferentes estados redox.
- Proponer un mecanismo para la unión y reducción del sustrato.
Principales métodos:
- Se utilizó la cristalografía de rayos X para determinar la estructura de la enzima.
- El análisis estructural se centró en el cofactor de molibdeno y su entorno de coordinación.
- Se realizaron comparaciones de secuencias con enzimas oxotransferasas relacionadas.
Principales resultados:
- La estructura cristalina reveló un cofactor monooxo molibdeno con dos dinucleótidos de guanina de molibdopterina.
- Se observó una coordinación asimétrica del molibdeno por grupos de metioleno.
- Se identificó la coordinación diferencial de pterina entre los estados oxidados (Mo ((VI)) y reducidos (Mo ((IV)).
- La cadena lateral de oxígeno del Ser147 coordina consistentemente el molibdeno.
Conclusiones:
- Los cambios observados en la coordinación de la pterina sugieren un mecanismo de unión y reducción del sustrato.
- La DMSO reductasa comparte similitudes estructurales y de sitio activo con otras oxotransferasas que contienen dinucleótidos de guanina de molibdopterina.
- Esta visión estructural contribuye a comprender las funciones microbianas en los ciclos biogeoquímicos y la regulación del clima.
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