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Un principio mecanicista para el bombeo de protones por la citocromo c oxidasa

Kristina Faxén¹, Gwen Gilderson, Pia Adelroth

¹Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.

|September 9, 2005

Resumen

Se aclaró el mecanismo molecular del bombeo de protones en la citocromo c oxidasa (CytcO). El bombeo de protones está acoplado a la transferencia de protones al oxígeno en el sitio catalítico, no a la transferencia interna de electrones.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Molecular Biología Molecular
La bioenergética es la bioenergética.

Sus antecedentes:

La respiración celular en organismos aeróbicos utiliza complejos proteicos unidos a la membrana para la transferencia de electrones al oxígeno.
Este proceso genera un gradiente de protones electroquímico transmembrana esencial para la síntesis de ATP.
La citocromo c oxidasa (CytcO) es el complejo enzimático terminal, que reduce el O2 a H2O y bombea protones a través de la membrana.

Objetivo del estudio:

Determinar el mecanismo molecular del bombeo de protones impulsado por la transferencia de electrones en CytcO.
Para dilucidar cómo CytcO transloca protones a través de la membrana durante la reducción de oxígeno.

Principales métodos:

El estudio investigó el acoplamiento mecánico entre la transferencia de electrones y la translocación de protones en CytcO.
Se centró en el sitio catalítico donde el oxígeno se reduce a agua.

Principales resultados:

El bombeo de protones en CytcO está mecánicamente acoplado a la transferencia de protones a O2 en el sitio catalítico.
Este acoplamiento ocurre en lugar de estar vinculado a eventos internos de transferencia de electrones dentro del complejo.

Conclusiones:

Los hallazgos sugieren un nuevo principio para el funcionamiento de la bomba de protones impulsada por redox.
Este mecanismo impone restricciones significativas a las posibles vías moleculares para la translocación de protones por CytcO.

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