Energy transduction in the sodium F-ATPase of Propionigenium modestum.
نویسندگان
چکیده
The F-ATPase of the bacterium Propionigenium modestum is driven by an electrochemical sodium gradient between the cell interior and its environment. Here we present a mechanochemical model for the transduction of transmembrane sodium-motive force into rotary torque. The same mechanism is likely to operate in other F-ATPases, including the proton-driven F-ATPases of Escherichia coli.
منابع مشابه
Torque generation by the Fo motor of the sodium ATPase.
Based on recent structural and functional findings, we have constructed a mathematical model for the sodium-driven Fo motor of the F1Fo-ATPase from the anaerobic bacterium Propionigenium modestum. The model reveals the mechanochemical principles underlying the Fo motor's operation, and explains all of the existing experimental data on wild-type and mutant Fo motors. In particular, the model pre...
متن کاملLife by a new decarboxylation-dependent energy conservation mechanism with Na as coupling ion.
We report here a new mode of ATP synthesis in living cells. The anaerobic bacterium Propionigenium modestum gains its total energy for growth from the conversion of succinate to propionate according to: succinate + H(2)O --> propionate + HCO(3) ( big up tri, openG' = -20.6 kJ/mol). The small free energy change of this reaction does not allow a substrate-linked phosphorylation mechanism, and no ...
متن کاملIdentification of aqueous access residues of the sodium half channel in transmembrane helix 5 of the Fo-a subunit of Propionigenium modestum ATP synthase
The Fo-a subunit of the Na+-transporting FoF1 ATP synthase from Propionigenium modestum plays a key role in Na+ transport. It forms half channels that allow Na+ to enter and leave the buried carboxyl group on Fo-c subunits. The essential Arg residue R226, which faces the carboxyl group of Fo-c subunits in the middle of transmembrane helix 5 of the Fo-a subunit, separates the cytoplasmic side an...
متن کاملMode of interaction of the single a subunit with the multimeric c subunits during the translocation of the coupling ions by F1F0 ATPases.
We have recently isolated a mutant (aK220R, aV264E, aI278N) of the Na+-translocating Escherichia coli/Propionigenium modestum ATPase hybrid with a Na+-inhibited growth phenotype on succinate. ATP hydrolysis by the reconstituted mutant ATPase was inhibited by external (N side) NaCl but not by internal (P side) NaCl. In contrast, LiCl activated the ATPase from the N side and inhibited it from the...
متن کاملCrucial role of the membrane potential for ATP synthesis by F(1)F(o) ATP synthases.
ATP, the universal carrier of cell energy, is manufactured from ADP and phosphate by the enzyme ATP synthase using the free energy of an electrochemical gradient of protons (or Na(+)). The proton-motive force consists of two components, the transmembrane proton concentration gradient (delta pH) and the membrane potential. The two components were considered to be not only thermodynamically but a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 96 9 شماره
صفحات -
تاریخ انتشار 1999