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1.
The redox-enzyme ferredoxin-NADP-oxidoreductase has been shown to be activated by light and inactivated in the dark. This review will summarize recent data concerning the biochemical characterization of the enzyme compared to its in-vivo activation. Further-more the mechanism of this activation process is discussed as a conformational change caused by the light-driven proton gradient.Abbreviations cyt
cytochrome
- fd
ferredoxin
- FNR1
large form of ferredoxin-NADP-oxidoreductase
- FNRox
oxidized FNR
- FNRred
reduced FNR
- FNRs
small form of FNR
- FNRsq
FNR-semiquinone 相似文献
2.
Regulation of oxidative phosphorylation: The flexible respiratory network ofParacoccus denitrificans
3.
Naoko Sakihama Izumi Nishimura Shigehiro Obata Masateru Shin 《Photosynthesis research》1995,46(1-2):323-328
When 35%-acetone extract of spinach chloroplasts was separated by SDS-PAGE, ferredoxin-NADP reductase (FNR) appeared as a single band at a molecular mass of 35 kDa. After the polypeptides on the SDS-PAGE plate were electroblotted onto PVDF membrane, the FNR band was cut out and analyzed for N-terminal structure in a gas-phase protein sequencer. Two different FNR peptides were identified: one with glutamine at its N-terminus (Gln-FNR) and the other with -pyroglutamic acid (FNR). Next, tightly bound FNR (tFNR) fraction was extracted from chloroplasts with their loosely bound FNR (lFNR) fraction removed in advance. The tFNR fraction contained Gln-FNR only. The Gln-FNR could be highly purified by affinity chromatography using a ferredoxin column. The purified Gln-FNR was digested with arginyl endopeptidase for peptide mapping and partial sequence analysis. Primary structure of Gln-FNR differed from that of FNR previously reported by Karplus et al. (1984) only in that it has an unblocked N-terminus. Highly purified Gln-FNR gave a molecular mass of 35 kDa in SDS-PAGE analysis, but its apparent molecular mass was estimated to be 38.5 kDa by gel-filtration HPLC analysis. This larger apparent molecular mass of Gln-FNR could be ascribed to its N-terminal moiety with around 15 amino acid residues protruding outside of a globular FNR molecule.Abbreviation CBB
Coomassie Brilliant Blue
- dabsyl chloride
(dimethylamino)azobenzenesulfonyl chloride
- FNR
ferredoxin-NADP reductase
- Gln-FNR
FNR with glutamine at N-terminus
- Ile-FNR
with isoleucine at N-terminus
-
lFNR
loosely bound FNR
-
tFNR
tightly bound FNR
- FNR
FNR with -pyroglutamic acid at N-terminus 相似文献
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5.
The binding of FNR to PSI has been postulated long ago, however, a clear evidence is still missing. In this work, using isothermal titration calorimetry (ITC), we found that FNR binds to photosystem I with its light harvesting complex I (PSI-LHCI) from C. reinhardtii with a 1:1 stoichiometry, a Kd of ~0.8 μM and ?H of ?20.7 kcal/mol. Titrations at different temperatures were used to determine the heat capacity change, ?CP, of the binding, through which the size of the interface area between the proteins was assessed as ~3000 Å2. In a different set of ITC experiments, introduction of various sucrose concentrations was used to estimate that ~95 water molecules are released to the solvent. These observations support the notion of a binding site shared by few of the photosystem I - light harvesting complex I (PSI-LHCI) subunits in addition to PsaE. Based on these results, a hypothetical model was built for the binding site of FNR at PSI, using known crystallographic structures of: cyanobacterial PSI in complex with ferredoxin (Fd), plant PSI-LHCI and Fd:FNR complex from cyanobacteria. FNR binding site location is proposed to be at the foot of the stromal ridge and above the inner LHCI belt. It is expected to form contacts with PsaE, PsaB, PsaF and at least one of the LHCI. In addition, a ~4.5-fold increased affinity between FNR and PSI-LHCI under crowded 1 M sucrose environment led us to conclude that in C. reinhardtii FNR also functions as a subunit of PSI-LHCI. 相似文献
6.
Complexes of Photosynthetic Redox Proteins Studied by NMR 总被引:2,自引:2,他引:0
Ubbink M 《Photosynthesis research》2004,81(3):277-287
In the photosynthetic redox chain, small electron transfer proteins shuttle electrons between the large membrane-associated redox complexes. Short-lived but specific protein:protein complexes are formed to enable fast electron transfer. Recent nuclear magnetic resonance (NMR) studies have elucidated the binding sites on plastocyanin, cytochrome c (6) and ferredoxin. Also the orientation of plastocyanin in complex with cytochrome f has been determined. Based on these results, general features that enable the formation of such transient complexes are discussed. 相似文献
7.
The effect of sodium cholate and other detergents (Triton X-100, sodium dodecyl sulphate, octyl glucoside, myristyltrimethylammonium bromide) on the reduction of plastoquinones (PQ) with a different length of the side-chain by spinach ferredoxin:NADP(+) oxidoreductase (FNR) in the presence of NADPH has been studied. Both NADPH oxidation and oxygen uptake due to plastosemiquinone autoxidation were highly stimulated only in the presence of sodium cholate among the used detergents. Sodium cholate at the concentration of 20 mM was found to be the most effective on both PQ-4 and PQ-9-mediated oxygen uptake. The FNR-dependent reduction of plastoquinones incorporated into sodium cholate micelles was stimulated by spinach ferredoxin but inhibited by Mg(2+) ions. It was concluded that the structure of sodium cholate micelles facilitates contact of plastoquinone molecules with the enzyme and creates favourable conditions for the reaction similar to those found in thylakoid membranes for PQ-9 reduction. The obtained results were discussed in terms of the function of FNR as a ferredoxin:plastoquinone reductase both in cyclic electron transport and chlororespiration. 相似文献
8.
铁氧还原白-NADP^+氧还酶(FNR)是光合电子传递中的关键酶之一。蓝细菌Synechococcus sp.PCC7002中编码FNR的petH基因被克隆到表达载体pET-3d上,在大肠杆菌中得到了高效表达,其表达量占大肠杆菌总蛋白的505%以上。高效表达的产物以可溶性和包含体两种形式存在。可溶性部分具有FNR的酶活性,在经过离子交换和凝胶层析后产生了电泳纯的FNR。包含体形式的部分经6.7mo 相似文献
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10.
Schistosoma mansoni: ferredoxin-NADP(H) oxidoreductase and the metabolism of reactive oxygen species
Mitochondrial-type ferredoxin-NADP(H) oxidoreductases (FNR) catalyze the electron transport between NADPH and substrates such as ferredoxins. Even though enzymes belonging to this family are present in several organisms, including prokaryotes, their biological function is not clearly understood. In a previous work, we reported the existence of a mitochondrial-type FNR in the trematode Schistosoma mansoni (SmFNR). This enzyme conferred tolerance to oxidative stress conditions when tested in an heterologous system. In this work, we demonstrate that the SmFNR can be imported to mitochondria in mammal cells and show that its expression is induced in parasite cultures by reactive oxygen species (ROS). The results reported herein give further support to the involvement of SmFNR in ROS metabolism. 相似文献