MF_01398

ATP synthase subunit b [atpF]

HAMAP entry
Member databaseHAMAP
HAMAP typefamily
Short nameATP_synth_b_bprime

Description
Imported from IPR002146

Transmembrane ATPases are membrane-bound enzyme complexes/ion transporters that use ATP hydrolysis to drive the transport of protons across a membrane. Some transmembrane ATPases also work in reverse, harnessing the energy from a proton gradient, using the flux of ions across the membrane via the ATPase proton channel to drive the synthesis of ATP.

F-ATPases (also known as ATP synthases, F1F0-ATPase, or H(+)-transporting two-sector ATPase) (
7.1.2.2
) are composed of two linked complexes: the F1 ATPase complex is the catalytic core and is composed of 5 subunits (alpha, beta, gamma, delta, epsilon), while the F0 ATPase complex is the membrane-embedded proton channel that is composed of at least 3 subunits (A-C), with additional subunits in mitochondria. Both the F1 and F0 complexes are rotary motors that are coupled back-to-back. In the F1 complex, the central gamma subunit forms the rotor inside the cylinder made of the α(3)β(3) subunits, while in the F0 complex, the ring-shaped C subunits forms the rotor. The two rotors rotate in opposite directions, but the F0 rotor is usually stronger, using the force from the proton gradient to push the F1 rotor in reverse in order to drive ATP synthesis
[1]
. These ATPases can also work in reverse in bacteria, hydrolysing ATP to create a proton gradient.

This entry represents subunits b and b' from the F0 complex in F-ATPases found in chloroplasts and in bacterial plasma membranes. The b subunits are part of the peripheral stalk that links the F1 and F0 complexes together, and which acts as a stator to prevent certain subunits from rotating with the central rotary element. The peripheral stalk differs in subunit composition between mitochondrial, chloroplast and bacterial F-ATPases. In bacterial and chloroplast F-ATPases, the peripheral stalk is composed of one copy of the delta subunit (homologous to OSCP in mitochondria), and two copies of subunit b in bacteria, or one copy each of subunits b and b' in chloroplasts and photosynthetic bacteria
[2]
.

References
Imported from IPR002146

1.Resolution of distinct rotational substeps by submillisecond kinetic analysis of F1-ATPase. Yasuda R, Noji H, Yoshida M, Kinosita K Jr, Itoh H. Nature 410, 898-904, (2001). View articlePMID: 11309608

2.Structure of the F1-binding domain of the stator of bovine F1Fo-ATPase and how it binds an alpha-subunit. Carbajo RJ, Kellas FA, Runswick MJ, Montgomery MG, Walker JE, Neuhaus D. J. Mol. Biol. 351, 824-38, (2005). View articlePMID: 16045926

Further reading

3. F-and V-ATPases in the genus Thermus and related species. Radax C, Sigurdsson O, Hreggvidsson GO, Aichinger N, Gruber C, Kristjansson JK, Stan-Lotter H. Syst. Appl. Microbiol. 21, 12-22, (1998). PMID: 9741106

4. F-type or V-type? The chimeric nature of the archaebacterial ATP synthase. Schafer G, Meyering-Vos M. Biochim. Biophys. Acta 1101, 232-5, (1992). PMID: 1385979

5. New insights into structure-function relationships between archeal ATP synthase (A1A0) and vacuolar type ATPase (V1V0). Gruber G, Marshansky V. Bioessays 30, 1096-109, (2008). View articlePMID: 18937357

6. Regulation and isoform function of the V-ATPases. Toei M, Saum R, Forgac M. Biochemistry 49, 4715-23, (2010). View articlePMID: 20450191

7. Mechanisms of ATPases--a multi-disciplinary approach. Rappas M, Niwa H, Zhang X. Curr. Protein Pept. Sci. 5, 89-105, (2004). View articlePMID: 15078220

8. The evolution of A-, F-, and V-type ATP synthases and ATPases: reversals in function and changes in the H+/ATP coupling ratio. Cross RL, Muller V. FEBS Lett. 576, 1-4, (2004). View articlePMID: 15473999

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