Chloroplast coupling factor

Younis, H.M., Weber, G. Boyer, J.S. (1983). Activity and conformational changes in chloroplast coupling factor induced by ion binding Formation of a magnesium-enzyme-phosphate complex. Biochemistry, 22, 2505-12. 

Baird, B.A., and Hammes, G.G. (1976) Chemical cross-linking studies of chloroplast coupling factor 1. J. Biol. Chem. 251, 6953-6962. 

Snyder, B., and Hammes, G. G. (1984) Structural mapping of chloroplast coupling factor. Biochemistry 23, 5787—5795. 

Fig. 9. (A) Schematic representation of photophosphoryiation in a reconstituted iiposome containing photosystem-l reaction centers and CFo Fi ATP synthase, both purified from spinach chloroplasts, using PMS as the electron donor/acoeptor system. (B) Rate of photophosphoryiation as a function of light intensity (left) and time dependence of reconstituted photophosphoryiation (right). Figure source (B) Hauska, Samoray, Orlich and Nelson (1980) Reconstitution of photosynthetic energy conservation. II. Photophosphoryiation in liposomes containing photosystem-l reaction center and chloroplast coupling-factor complex. Eur J Biochem 111 540.

ML Richter, Z Gromet-Elhanan and R McCarty (1986) Reconstitution ofthe Ft ATPase of Rhodospirlllum rubrum by the P subunit of chloroplast coupling factor. J Biol Chem 261 12109-12113... 

JV Maroney, L Lopresti, BF McEwen, RE McCarty and GG Hammes (1983) The M-value of chloroplast coupling factor 1. FEBS Lett 158 58-62... 

N Nelson and O Karny (1976) The role of S subunit in the coupling activity of chloroplast coupling factor 1. FEBS Lett 70 249-252... 

The five polypeptides of chloroplast coupling factor one (CFi) have a subunit stoichiometry of 3a, 3p, Y, 5, e designated in order of decreasing molecular weight (1-3). Nucleotide binding and ATPsynthase/ATPase activity have been associated with the p subunit per CFi and evidence suggests that the three active sites are functionally linked (4). Purified CFi is a latent ATPase which can be activated to show specificity for Mg (5-8) or Ca (9-12). 

The Fi portion of the ATP synthase has three copies of the P subunit which is thought to contain the nucleotide-binding/catalytic sites of the enzyme. We recently described a procedure for isolating this important subunit from spinach chloroplast coupling factor 1 (CFi) and showed that it was able to restore both ATP hydrolysis and a low rate of ATP synthesis to chromatophores of Rhodospirillum rubrum which lacked the native P subunit. ... 

In a precedent work (7) we have applied it to the fixation of ADP and ATP on chloroplast coupling factor CFl and on some of its subunits. This protein is a part of a proton translocating multisubunit enzyme found in photosynthetic membranes and is able to hydrolyse and synthesize ATP. We have shown by this method that CFl possesses six binding sites two high affinity sites for ADP or ATP (Kd=1-5 10 in addition to one site where endogenous not exchangeable ADP is bound, and three low affinity sites binding ADP or ATP with a dissociation constant of 15-20 10 il, responsible for the catalytic activity. 

ATP SYNTHESIS BY ISOLATED CHLOROPLAST COUPLING FACTORS, INDUCED WITH pH-SHIFT... 

Broken chloroplasts were isolated from spinach, cv. Monatol, as described in ref. (5). The isolation of chloroplast coupling factor (CFl) was performed as in ref. (6). ATP hydrolysis was followed by liberation of 32P)-phosphate from (32P)-labelled ATP (7) Dibucaine (2-butoxy- N-2(diethylamino)ethyl)-4-quinolinocarboxyamide) and chlor-promazine (2-chloro-lO- -3 dimethylaminopropyl)-phenothiazine) were used as t-amines. 

Abbreviations used Fi Fq, H+-translocating ATP synthases from mitochondria, E. coli plasma membranes, plasma membranes of the thermophilic bacterium PS3 and chloroplast membranes CFi, chloroplast coupling factor one ATPase, CFiE. C. 3.6.1.3 SDS-PAGE, polyacrylamide gel electrophoresis in the presence of sodium dodecyl... 

Ate, adenylate energy charge CF, chloroplast coupling factor 1 PFK, phosphofructokinase PK, pyruvate kinase GK, glycerokinase PMS, phenazi nemethosulfate. 

Diurnal Pattern of Chloroplast Coupling Factor Oxidation Kinetics in Leaves of Intact... 

ATP Synthesis by Isolated Chloroplast Coupling Factors, Induced with pH-Shift 105... 

Various pathotypes also produce a cyclic tetrapep-tide known as tentoxin (Fig. 2) which induces chlorosis in many plants (e.g. lettuce, potato, cucumber, spinach), but not in Nicotiana, tomato, cabbage or radish. It binds to chloroplast coupling factor 1 (one toxin-binding site per aP subunit complex), inhibiting photophosphorylation and the Ca -dependent ATP-ase. Species specificity is due to different binding affinities for coupling factor 1 (1.3-20 x lO M for 50% inhibition in sensitive species, and 20-fold higher for insensitive species). 

Affinity Labeling of ATPase Rabbit Muscle Myosin and Chloroplast Coupling Factor 1... 

Here, associated with the adenilate-kinase-like reaction (2ADP ATP -h AMP). This adenilatekinase-like reaction catalyzed by the chloroplast coupling factor CFi was demonstrated in the laboratory of Moudrianakis [181]. 

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