FiFo-ATP synthase

FIGURE 22.17 The R. viridis reaction center is coupled to the cytochrome h/Cl complex through the quinone pool (Q). Quinone molecules are photore-duced at the reaction center Qb site (2 e [2 hv] per Q reduced) and then diffuse to the cytochrome h/ci complex, where they are reoxidized. Note that e flow from cytochrome h/ci back to the reaction center occurs via the periplasmic protein cytochrome co- Note also that 3 to 4 are translocated into the periplasmic space for each Q molecule oxidized at cytochrome h/ci. The resultant proton-motive force drives ATP synthesis by the bacterial FiFo ATP synthase. (Adapted from Deisenhofer, and Michel, H., 1989. The photosynthetic reaction center from the purple bac-terinm Rhod.opseud.omoaas viridis. Science 245 1463.)... 

ATP synthesis is the final step in the conservation of energy via chemios-mosis. This step is catalyzed by FiFo ATP synthase, a multisubunit enzyme complex found exclusively in cytoplasmic membranes of bacteria (Senior 1988). It uses the chemiosmotic energy (ApH) generated from membrane ET to synthesize ATP from ADP and Pi. The most investigated bacterial... 

The Molecular Mechanism of ATP Synthesis by FiFo-ATP Synthase A Scrutiny of the Major Possibilities 77... 

Membrane-bound FiFo-ATP synthase is easily dissociated into a water-soluble coupling factor F and a membrane-bound F0. The isolated Fj... 

Zhang, Y., Oldenburg, M., and Fillingame, R. H. (1994). Suppressor mutations in Fj subunit t recouple ATP-driven H+ translocation in uncoupled Q42E subunit c mutant of Escherichia coli FiFo ATP synthase./. Biol. Chem. 269, 10221-10224. 

Shin YK, Yoo BC, Chang HJ, Jeon E, Hong SH, Jung MS, et al. Down-regulation of mitochondrial FIFO-ATP synthase in human colon cancer cells with induced 5-fluorouracil resistance. Cancer Res 2005 65(8)3162-3170. 

Liu et al. have described the solution structure of a mutant of the homodimer protein transcription factor 1, TFl. The dimeric core, consisting of the N-terminal helices and beta sheets, is more tightly packed than wire type, and this might be responsible for its increased thermal stability. Also, Gordon-Smith et al reported the dimeric structure of a C-terminal fragment of Bovine IFl, which inhibits the hydrol) ic action of the FIFO ATP synthase in mitochondria under anaerobic conditions. Most imusually, the molecule forms an anti-parallel coiled-coil in which three histidine residues occupy key positions at the dimer interface. ... 

Girvin ME, Fillingame RH (1995) Determination of local protein structure by spin-label difference 2D NMR the region neighboring Asp61 of subunit-c of the FIFO ATP synthase. Biochemistry 34 1635-1645... 

R.H. Fillingame, C.M. Angevine, and O.Y. Dmitriev, Coupling Proton Movements to c-Ring Rotation in FIFO ATP Synthase Aqueous Access Channels and Helix Rotations at the a-c Interface. Biochim. Biophys. Acta, 1555, 29-36,2002. 

Weber J, Senior AE ATP synthesis driven by proton transport in FIFO-ATP synthase. FEBS Lett 2003, 545(l) 6l—70. 

Nath, S. (2002). The molecular mechanism of ATP synthesis by FIFO-ATP synthase a scrutiny of the major possibilities. Adv Biochem Eng Biotechnol 74, 65-98. 

Deckers-Hebestreit G, Altendorf K. 1996. The FiFo-type ATP synthases of bacteria structure and function of the Fq complex. Annu Rev Microbiol 50 791-824. 

Capaldi, R.A., and Aggeler, R. 2002. Mechanism of the FIFO-type ATP synthase, a biological rotary motor. Trends Biochem. Sci. 27 154—160. 

Three types of ATP-driven cation pumps can be distinguished on the basis of their structure and their sensitivity to inhibitors. They are the E E2-ATPases, the FiFo-proton-translocating ATP synthase, and the vacuolar ATPases which are designated as P-, F-, and V-type ATPases, respectively [37]. Several of the distinguishing characteristics of these enzymes are summarized in Table 1. The F- and V-ATPases can be differentiated by the sensitivity of the former to azide and the latter to nitrate and A-ethylmaleimide (NEM)[38]. In addition, the V-ATPases are exquisitely sensitive to the antibiotic bafilomycin A [39,40]. 

Within the process of oxidative phosphorylation the mitochondrial ATP synthase (also referred synonymously as complex V, FiFo-ATPase or FiFq-ATP synthase) has to fulfill two main tasks ... 

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