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Arquitectura del dominio de la piruvato carboxilasa, una enzima multifuncional dependiente de la biotina
Martin St Maurice1, Laurie Reinhardt, Kathy H Surinya
1Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA.
Science (New York, N.Y.)
|August 25, 2007
Resumen
Las enzimas dependientes de la biotina, cruciales para el metabolismo y dirigidas a la diabetes y la obesidad, transfieren grupos carboxilo. Este estudio revela su estructura y mecanismo, mostrando transferencia entre cadenas y activación alostérica.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Biología Estructural Biología estructural.
Sus antecedentes:
- Las enzimas dependientes de la biotina catalizan las transferencias esenciales de grupos carboxilo.
- Estas enzimas están implicadas en enfermedades metabólicas como la obesidad y la diabetes tipo 2.
- El mecanismo de transferencia del grupo carboxilo en estas enzimas es poco conocido.
Objetivo del estudio:
- Para aclarar la base estructural de la transferencia del grupo carboxilo en las enzimas dependientes de la biotina.
- Para comprender el mecanismo de activación alostérica en la carboxilasa de piruvato.
Principales métodos:
- Cristalografía de rayos X a una resolución de 2.0 angstroms para determinar la estructura de la enzima.
- Análisis mutagénico para investigar la función enzimática y la transferencia intermedia.
Principales resultados:
- Se resolvió la disposición completa del dominio de la piruvato carboxilasa.
- La evidencia sugiere que la transferencia intermedia ocurre entre sitios activos en cadenas polipéptidas separadas.
- Las reorganizaciones de dominio tras la unión del activador reducen las distancias del sitio interactivo, lo que explica la activación alostérica.
Conclusiones:
- El estudio proporciona información estructural sobre la función de las enzimas dependientes de la biotina.
- Se propone un nuevo paradigma para la catálisis enzimática multifuncional que implica la transferencia entre cadenas y la regulación alostérica.
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