ATP-Dependent Electron Activation Module of Benzoyl-Coenzyme A Reductase from the Hyperthermophilic Archaeon Ferroglobus placidus.
Biochemistry
; 55(39): 5578-5586, 2016 Oct 04.
Article
em En
| MEDLINE
| ID: mdl-27597116
ABSTRACT
The class I benzoyl-coenzyme A (BzCoA) reductases (BCRs) are key enzymes in the anaerobic degradation of aromatic compounds that catalyze the ATP-dependent dearomatization of their substrate to a cyclic dienoyl-CoA. The phylogenetically distinct Thauera- and Azoarcus-type BCR subclasses are iron-sulfur enzymes and consist of an ATP-hydrolyzing electron activation module and a BzCoA reduction module. More than 20 years after their initial identification, all biochemical information about class I BCRs derives from studies of the wild-type enzyme from the denitrifying bacterium Thauera aromatica (BCRTaro). Here, we describe the first heterologous production and purification of the ATP-hydrolyzing, electron-activating module of an Azoarcus-type BCR from the hyperthermophilic archaeon Ferroglobus placidus, BzdPQFpla. The Fe content, UV/vis spectroscopic, and Mössbauer spectroscopic properties of the 57Fe-enriched enzyme clearly identified a [4Fe-4S]+/2+ cluster with a redox potential (E°') of -376 mV as a cofactor. ATP hydrolysis is required to overcome a redox barrier of â¼250 mV for stoichiometric electron transfer from the [4Fe-4S]+ cluster to the substrate benzene ring (E°'BzCoA/dienoyl-CoA = -622 mV). BzdPQFpla exhibited ATPase activity (15 nmol min-1 mg-1; Km = 270 µM) at 75 °C, which was relatively stable in air in contrast to BCRTaro. The results obtained revealed high levels of functional and molecular similarity between Azoarcus-type BCRs and the homologous ATP-dependent activator components of 2-hydroxyacyl-CoA dehydratases involved in amino acid fermentations. Insights into the diversity and evolution of ATP-dependent electron-activating modules for catalytic or stoichiometric low-potential electron transfer processes are presented.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Trifosfato de Adenosina
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Archaea
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Oxirredutases atuantes sobre Doadores de Grupo CH-CH
Idioma:
En
Revista:
Biochemistry
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Alemanha