Essential arginine residue of the Fo-a subunit in FoF1-ATP synthase has a role to prevent the proton shortcut without c-ring rotation in the Fo proton channel
In: Biochemical Journal, Jg. 430 (2010-07-28), S. 171-177
Online
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Zugriff:
In F(o)F(1) (F(o)F(1)-ATP synthase), proton translocation through F(o) drives rotation of the oligomer ring of F(o)-c subunits (c-ring) relative to F(o)-a. Previous reports have indicated that a conserved arginine residue in F(o)-a plays a critical role in the proton transfer at the F(o)-a/c-ring interface. Indeed, we show in the present study that thermophilic F(o)F(1s) with substitution of this arginine (aR169) to other residues cannot catalyse proton-coupled reactions. However, mutants with substitution of this arginine residue by a small (glycine, alanine, valine) or acidic (glutamate) residue mediate the passive proton translocation. This translocation requires an essential carboxy group of F(o)-c (cE56) since the second mutation (cE56Q) blocks the translocation. Rotation of the c-ring is not necessary because the same arginine mutants of the 'rotation-impossible' (c(10)-a)F(o)F(1), in which the c-ring and F(o)-a are fused to a single polypeptide, also exhibits the passive proton translocation. The mutant (aR169G/Q217R), in which the arginine residue is transferred to putatively the same topological position in the F(o)-a structure, can block the passive proton translocation. Thus the conserved arginine residue in F(o)-a ensures proton-coupled c-ring rotation by preventing a futile proton shortcut.
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Essential arginine residue of the Fo-a subunit in FoF1-ATP synthase has a role to prevent the proton shortcut without c-ring rotation in the Fo proton channel
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Autor/in / Beteiligte Person: | Ono, Sakurako ; Yoshida, Masasuke ; Sone, Nobuhito ; Mitome, Noriyo ; Sato, Hiroki ; Suzuki, Toshiharu |
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Zeitschrift: | Biochemical Journal, Jg. 430 (2010-07-28), S. 171-177 |
Veröffentlichung: | Portland Press Ltd., 2010 |
Medientyp: | unknown |
ISSN: | 1470-8728 (print) ; 0264-6021 (print) |
DOI: | 10.1042/bj20100621 |
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