Fluid mechanical matching of H+-ATP synthase subunit c-ring with lipid membranes revealed by2H solid-state NMR

Masatoshi Kobayashi, Andrey V. Struts, Toshimichi Fujiwara, Michael F. Brown, Hideo Akutsu

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

The F1 F0-ATP synthase utilizes the transmembrane H+ gradient for the synthesis of ATP. F0 subunit c-ring plays a key role in transporting H+ through F0 in the membrane. We investigated the interactions of Escherichia coli subunit c with dimyristoylphosphatidylcholine (DMPC-d54) at lipid/protein ratios of 50:1 and 20:1 by means of 2H-solid-state NMR. In the liquid-crystalline state of DMPC, the 2H-NMR moment values and the order parameter (SCD) profile were little affected by the presence of subunit c, suggesting that the bilayer thickness in the liquid-crystalline state is matched to the transmembrane hydrophobic surface of subunit c. On the other hand, hydrophobic mismatch of subunit c with the lipid bilayer was observed in the gel state of DMPC. Moreover, the viscoelasticity represented by a square-law function of the 2H-NMR relaxation was also little influenced by subunit c in the fluid phase, in contrast with flexible nonionic detergents or rigid additives. Thus, the hydrophobic matching of the lipid bilayer to subunit c involves at least two factors, the hydrophobic length and the fluid mechanical property. These findings may be important for the torque generation in the rotary catalytic mechanism of the F1F 0-ATPse molecular motor.

Original languageEnglish (US)
Pages (from-to)4339-4347
Number of pages9
JournalBiophysical Journal
Volume94
Issue number11
DOIs
StatePublished - Jun 1 2008

ASJC Scopus subject areas

  • Biophysics

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