The Proton-Translocating F0F1 ATP Synthase-ATPase Complex

Assembled F1-(αβ) and Hybrid F1-α3β3γ-ATPases fromRhodospirillum rubrum α, Wild Type or Mutant β, and Chloroplast γ Subunits

“…A recombinant CF 1 -␥ C subunit was used for these studies since there is as yet no available native or recombinant ␥ R . This ␥ C was found to assemble with the native unstable CF 1 (11), and its incubation with the isolated ␣ (Fig. 2, A and B).…”

“…The catalytic F 1 sector, which functions as a soluble ATPase, has in all cells a subunit composition of ␣ 3 ␤ 3 ␥ 1 ␦ 1 ⑀ 1 and six nucleotide-binding sites located on the ␣ and ␤ subunits. Its three catalytic ␤ sites show high negative cooperativity in substrate binding and strong positive cooperativity in catalysis (1)(2)(3)(4)(5). The minimal F 1 subcomplex, which resembles the whole F 1 -ATPase in its catalytic properties, is the F 1 -␣ 3 ␤ 3 ␥-ATPase.…”

“…A high resolution x-ray structure of the bovine heart mitochondrial MF 1 (12) demonstrated the alternating arrangement of the ␣ and ␤ subunits in a closed hexamer, with the resolved N-and C-terminal ␣-helices of the ␥ subunit embedded in its central cavity and all six nucleotide-binding sites residing at alternating ␣/␤ interfaces. The three catalytic sites, located mainly on the ␤ subunits, appeared in three different conformational states that, in association with the unique resolved part of the ␥ subunit, imposed an asymmetric structure on the ␣ 3 ␤ 3 hexamer (12).…”

“…Tight regulation of ATP hydrolysis is especially important in photosynthetic cells, where it prevents the depletion of essential cellular ATP pools in the dark (1,4,5). Plant chloroplasts and bacterial chromatophores have a number of such regulatory pathways, which operate in their membranebound F 0 F 1 -as well as the solubilized F 1 -ATPases.…”

Hybrid Rhodospirillum rubrumF0F1 ATP Synthases Containing Spinach Chloroplast F1 β or α and β Subunits Reveal the Essential Role of the α Subunit in ATP Synthesis and Tentoxin Sensitivity

“…The general structure of these ATP synthases is highly conserved, consisting of F 0 , the membrane-spanning proton channel, and F 1 , the peripheral membrane sector, which contains the catalytic sites for reversible ATP synthesis. The F 0 is composed of four different subunits labeled a, b, bЈ, and c in photosynthetic bacteria (1) and I-IV in chloroplasts (2)(3)(4). The chloroplast F 0 subunits IV, I, II, and III are analogous to the bacterial a, b, bЈ, and c, respectively, with a probable stoichiometry of a 1 b 1 bЈ 1 c 9 -12 .…”