ATPase complex

Haetmann-Peteesen, R., Tanaka, K., and Hendil, K. B. Quaternary structure of the ATPase complex of human 26 S proteasomes determined by chemical cross-linking. Arch Biochem Biophys 2001, 386, 89-94. 

Hoeeman, L. and Reghsteinee, M. Activation of the multicatalytic protease. The 11 S regulator and 20S ATPase complexes contain distinct 30-kilodalton subunits. J. Biol. Chem. 1994, 269, 16890-16895. 

S. H. Crystal structures of the HslVU peptidase-ATPase complex reveal an ATP-... 

Guschin, D., Geiman, T.M., Kikyo, N., Tremethick, D.J., Wolffe, A.P., and Wade, P.A. (2000) Multiple ISWI ATPase complexes from Xenopus laevis. Functional conservation of an ACF/ CHRAC homolog. J. Biol. Chem. 275, 35248-35255. 

F,F ATPase COMPLEX REACTION ELEMENTARY REACTION PRIMITIVE CHANGE PARALLEL REACTIONS SERIES REACTIONS OOMPONENT... 

Arata, Y., Baleja, J. D., and Forgac, M. (2002a). Localization of subunits D, E, and G in the yeast V-ATPAse complex using cysteine mediated cross-linking to subunit B. Biochemistry 41, 11301-11307. 

Xu, T., Vasilyeva, E., and Forgac, M. (1999). Subunit interactions in the clathrin-coated vesicle V-ATPase complex./. Biol. Chem. 274, 28909-28915. 

Figure 7. Effect of fi, y-bidentate CrATP on the signal intensity of the Mn2 -(Na 4- K )-ATPase complex...

The binding of Gd3+ to Ca2+-ATPase was also examined using water proton nuclear relaxation rates. Figure 11 shows the behavior of the observed enhancement of the longitudinal water proton relaxation rate when Gd3+ is used to titrate a solution of the Ca2" "-ATPase. At the lower concentrations of Gd3" " the large observed enhancement of the water proton relaxation rate suggests the formation of a tight binary Gd3+-ATPase complex. 

Such a decrease in the linewidth may result from a decrease in the Gd3+ coordination number upon formation of the macromolecular complex, which could result in greater symmetry and a lower zero-field splitting for the Gd3+ ion. This spectrum is independent of temperature between 4 and 25°C and is independent of the Gd3+/ ATPase ratio up to 2 Gd + ions/ATPase molecule. The peak-to-peak linewidth of 285 G sets a lower limit of 2,3 x 10"10s Qn the electron spin relaxation time of enzyme-bound Gd +t This symmetric, narrow EPR spectrum for the Gd3+-ATPase complex is compared in Figure 13B to that of Gd3+ bound to parvalbumin, a Ca2+-binding protein from carp. In this case, the spectrum is extremely broad and suggests a greatly distorted Gd3+ coordination geometry compared to the Ca2+-ATPase. 

Three membrane-bound adenosine triphosphatase enzymes have been characterized using Mn(II) and Gd(III) electron paramagnetic resonance (EPR) and a variety of NMR techniques. Mn(II) EPR studies of both native and partially delipidated (Na+ + K+)-ATPase from sheep kidney indicate that the enzyme binds Mn2+ at a single, catalytic site with Kq = 0.21 x 10- M. The X-band EPR spectrum of the binary Mn(II)-ATPase complex exhibits a powder line shape consisting of a broad transition with partial resolution of the 55 n nuclear hyperfine structure, as well as a broad component to the low field side of the spectrum. ATP, ADP, AMP-PNP and Pj all broaden the spectrum, whereas AMP induces a substantial narrowing of the hyperfine lines of the spectrum. 

Vilsen, B. Andersen, J.P. (1992b). Interdependence of Ca2+ occlusion Sites in the unphosphorylated sarcoplasmic reticulum Ca2+-ATPase complex with CrATP. J. Biol. Chem. 267, 3539-3550. 

Focusing on the mechanisms of action of BOA into the plant cell, Barnes et al.7 suggested that the chlorotic seedlings observed in the presence of BOA and DIBOA could be the consequence of a benzoxazinone effect on the photophosphorylation and electron transport into the plant metabolism. In this way, Niemeyer et al.28 studied the effects of BOA on energy-linked reactions in mitochondria and reported an inhibition of the electron transfer between flavin and ubiquinone in Complex I, with complete inhibition of electron transport from NADH to oxygen in SMP. They could also detect an inhibition of BOA on ATP synthesis by acting directly on the ATPase complex at the F1 moiety. 

So that whole ATPase complex is a proton pumping device. 

The proton-ATPase complex, first purified by Pick and Racker [54], was reported to contain nine different subunits, four of which may belong to the membrane sector. Later studies in our laboratory detected only three subunits in the... 

Subunit structure and function of the proton ATPase complex... 

A chaperone-like function for a similar ATPase complex from S. shibatae [54], which showed a preferred binding to newly unfolded proteins, seems probable. To understand the real function of this ATPase complex, however, more detailed studies about its binding specificity are necessary. 

The isolation of an active, structurally intact complex was obtained using an association of cholate and octylglucoside and sucrose gradient centrifugation [111]. This preparation did not contain cytochrome 6-559 and possessed a plastoquinol-plastocyanine oxidoreductase activity, inhibited by specific inhibitors (DBMIB, UHDBT). The complex was essentially free of chlorophyll and contaminations by other membrane components, specifically of the ATPase complex. 

Ferredoxin-NADP" oxidoreductase is a flavoprotein bound to the membrane that can nevertheless be isolated as a water soluble homogeneous preparation [247]. The isolated enzyme has a molecular weight of 40000 and contains one mol of FAD per mol of apoprotein [248] its midpoint potential is -0.38 V at pH 7 [249]. The enzyme can also accept NAD" " as electron acceptor, but is very specific for ferredoxin as donor the formation of a 1 1 complex with this latter protein could be demonstrated by differential spectrophotometry [250]. Immunological studies have revealed the location of this flavoprotein on the stromal surface of the membrane, in the vicinity of the ATPase complexes and therefore predominantly on... 

Fig. 12.1. Relative sizes of mitochondrial and chloroplast chromosomes and location of protein structural genes. The figure was constructed from published data [5,15,17,22,26-28]. The structural genes are marked by wide sections. Black areas code for proteins. White areas are introns. 0x1, OxII and OxIII are subunits I, II and III of cytochrome c oxidase. Cyt b, cytochrome b. Fo and Fo, are subunits 6 and 9 of the proton ATPase complex. In the chloroplast chromosome the arrows indicate the transcription direction and the size of the transcripts. CF,a, CFj/8, CFjc and CFoIII are subunits a, /S, t and III of the chloroplast proton ATPase complex [30]. PSII5], PSII44, and PSII34 are subunits of photosystem II reaction center with the corresponding molecular weights of 51000, 44000 and 34000. PSI70 is subunit I of photosystem I reaction center. Cyt /is cytochrome/ cyt is cytochrome b and b -flV is subunit IV of cytochrome b(,-f complex.

Sabbert, Engelbrecht and Junge " modified a chloroplast CF, -ATPase complex by labeling its y-subunit with eosin-5-maleimide (abbreviated as e5m) [Fig. 34 (A)]. It is known thateSm forms a covalent bond with Cys-322 in the y-subunit of CF,. The specific labeling by eosin was confirmed by fluorescence of the y-subunit band on SDS-PAGE viewed under U V-illumination. A sample was then prepared in which the e5m-labeled CF, is immobilized on an anion-exchange resin (Saphadex DEAE-50). 

Z Gromet-Elhanan (1995) The proton-translocatingFqF ATP synthase-ATPase complex r RE Blankenship, MT Madigan and CE Bauer (eds) Anoxygenic Photosynthetic Bacteria, pp. 807-830. Kluwer. 

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