ATP hydrolysis and synthesis by the membrane-bound ATP synthetase complex of Methanobacterium thermoautotrophicum.
AUTOR(ES)
Doddema, H J
RESUMO
The membrane-bound ATP synthetase complex of Methanobacterium thermoautotrophicum showed maximum activity for ATP hydrolysis at pH 8, at temperatures between 65 and 70 degrees C, and at an ATP-Mg2+ ratio of 0.5. Anaerobic conditions were not prerequisite for enzyme activity. The enzyme showed a Km value for ATP of 2 mM, and activity was Mg2+ dependent; Mn2+, Co2+, Ca2+, and Zn2+ could replace Mg2+ to some extent. Other nucleoside triphosphates could be hydrolyzed. N,N'-dicyclohexylcarbodiimide inhibited ATP hydrolysis. A proton-motive force, artificially imposed by a pH shift or valinomycin, resulted in ATP synthesis in whole cells. The ATP synthetase complex of the thermophilic methanogenic bacterium is similar to those described in aerobic and anaerobic microorganisms.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=218627Documentos Relacionados
- Methanogenesis and ATP synthesis in a protoplast system of Methanobacterium thermoautotrophicum.
- Properties of a membrane-bound cardiolipin synthetase from Lactobacillus plantarum.
- ATP activation and properties of the methyl coenzyme M reductase system in Methanobacterium thermoautotrophicum.
- Activation of formylmethanofuran synthesis in cell extracts of Methanobacterium thermoautotrophicum.
- In vitro synthesis of A-particle structual protein by membrane-bound polyribosomes.
