Characterization of the relationship between ADP- and epsilon-induced inhibition in cyanobacterial F1-ATPase.
J Biol Chem
; 286(15): 13423-9, 2011 Apr 15.
Article
em En
| MEDLINE
| ID: mdl-21345803
ABSTRACT
The ATPase activity of chloroplast and bacterial F(1)-ATPase is strongly inhibited by both the endogenous inhibitor ε and tightly bound ADP. Although the physiological significance of these inhibitory mechanisms is not very well known for the membrane-bound F(0)F(1), these are very likely to be important in avoiding the futile ATP hydrolysis reaction and ensuring efficient ATP synthesis in vivo. In a previous study using the α(3)ß(3)γ complex of F(1) obtained from the thermophilic cyanobacteria, Thermosynechococcus elongatus BP-1, we succeeded in determining the discrete stop position, â¼80° forward from the pause position for ATP binding, caused by ε-induced inhibition (ε-inhibition) during γ rotation (Konno, H., Murakami-Fuse, T., Fujii, F., Koyama, F., Ueoka-Nakanishi, H., Pack, C. G., Kinjo, M., and Hisabori, T. (2006) EMBO J. 25, 4596-4604). Because γ in ADP-inhibited F(1) also pauses at the same position, ADP-induced inhibition (ADP-inhibition) was assumed to be linked to ε-inhibition. However, ADP-inhibition and ε-inhibition should be independent phenomena from each other because the ATPase core complex, α(3)ß(3)γ, also lapses into the ADP-inhibition state. By way of thorough biophysical and biochemical analyses, we determined that the ε subunit inhibition mechanism does not directly correlate with ADP-inhibition. We suggest here that the cyanobacterial ATP synthase ε subunit carries out an important regulatory role in acting as an independent "braking system" for the physiologically unfavorable ATP hydrolysis reaction.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Difosfato de Adenosina
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Cianobactérias
/
ATPases Translocadoras de Prótons
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Japão