Jul 1, 2011
ATP binding to the ϵ subunit of thermophilic ATP synthase is crucial for efficient coupling of ATPase and H+ pump activities.
The Biochemical journal
- ,
- ,
- ,
- Volume
- 437
- Number
- 1
- First page
- 135
- Last page
- 40
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1042/BJ20110443
- Publisher
- PORTLAND PRESS LTD
ATP binding to the ϵ subunit of F1-ATPase, a soluble subcomplex of TFoF1 (FoF1-ATPase synthase from the thermophilic Bacillus strain PS3), affects the regulation of F1-ATPase activity by stabilizing the compact, ATPase-active, form of the ϵ subunit [Kato, S., Yoshida, M. and Kato-Yamada, Y. (2007) J. Biol. Chem. 282, 37618-37623]. In the present study, we report how ATP binding to the ϵ subunit affects ATPase and H+ pumping activities in the holoenzyme TFoF1. Wild-type TFoF1 showed significant H+ pumping activity when ATP was used as the substrate. However, GTP, which bound poorly to the ϵ subunit, did not support efficient H+ pumping. Addition of small amounts of ATP to the GTP substrate restored coupling between GTPase and H+ pumping activities. Similar uncoupling was observed when TFoF1 contained an ATP-binding-deficient ϵ subunit, even with ATP as a substrate. Further analysis suggested that the compact conformation of the ϵ subunit induced by ATP binding was required to couple ATPase and H+ pumping activities in TFoF1 unless the ϵ subunit was in its extended-state conformation. The present study reveals a novel role of the ϵ subunit as an ATP-sensitive regulator of the coupling of ATPase and H+ pumping activities of TFoF1.
- Link information
- ID information
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- DOI : 10.1042/BJ20110443
- ISSN : 0264-6021
- Pubmed ID : 21510843
- Web of Science ID : WOS:000292714500014