論文

2010年8月

F1F0-ATP synthases of alkaliphilic bacteria: Lessons from their adaptations

BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
  • David B. Hicks
  • ,
  • Jun Liu
  • ,
  • Makoto Fujisawa
  • ,
  • Terry A. Krulwich

1797
8
開始ページ
1362
終了ページ
1377
記述言語
英語
掲載種別
DOI
10.1016/j.bbabio.2010.02.028
出版者・発行元
ELSEVIER SCIENCE BV

This review focuses on the ATP synthases of alkaliphilic bacteria and, in particular, those that successfully overcome the bioenergetic challenges of achieving robust H+-coupled ATP synthesis at external pH values >10. At such pH values the protonmotive force, which is posited to provide the energetic driving force for ATP synthesis, is too low to account for the ATP synthesis observed. The protonmotive force is lowered at a very high pH by the need to maintain a cytoplasmic pH well below the pH outside, which results in an energetically adverse pH gradient. Several anticipated solutions to this bioenergetic conundrum have been ruled out. Although the transmembrane sodium motive force is high under alkaline conditions, respiratory alkaliphilic bacteria do not use Na+- instead of H+-coupled ATP synthases. Nor do they offset the adverse pH gradient with a compensatory increase in the transmembrane electrical potential component of the protonmotive force. Moreover, studies of ATP synthase rotors indicate that alkaliphiles cannot fully resolve the energetic problem by using an ATP synthase with a large number of c-subunits in the synthase rotor ring. Increased attention now focuses on delocalized gradients near the membrane surface and H+ transfers to ATP synthases via membrane-associated microcircuits between the H+ pumping complexes and synthases. Microcircuits likely depend upon proximity of pumps and synthases, specific membrane properties and specific adaptations of the participating enzyme complexes. ATP synthesis in alkaliphiles depends upon alkaliphile-specific adaptations of the ATP synthase and there is also evidence for alkaliphile-specific adaptations of respiratory chain components. (C) 2010 Elsevier B.V. All rights reserved.

リンク情報
DOI
https://doi.org/10.1016/j.bbabio.2010.02.028
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000279888700003&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.bbabio.2010.02.028
  • ISSN : 0005-2728
  • Web of Science ID : WOS:000279888700003

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