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1.
《BBA》1985,806(2):283-289
Treatment of Photosystem II particles with 1.2 M CaCl2 released three proteins of 33, 24 and 18 kDa of the photosynthetic oxygen evolution system, but left Mn bound to the particles as demonstrated by Ono and Inoue (Ono, T. and Inoue, Y. (1983) FEBS Lett. 164, 252–260). Oxygen-evolution activity of the CaCl2-treated particles was very low in a medium containing 10 mM NaCl as a salt, but could be restored by the 33-kDa protein. When the particles were incubated in 10 mM NaCl at 0°C, two of the four Mn atoms per oxygen-evolution system were released with concomitant loss of oxygen-evolution activity. The 33-kDa protein suppressed the release of Mn and the inactivation during the incubation. These findings from reconstitution experiments suggest that the 33-kDa protein acts to preserve Mn atoms in the oxygen-evolution system. The 33-kDa protein could be partially substituted by 100 or 150 mM Cl− for the preservation of the Mn and oxygen-evolution activity. The Mn in Photosystem II particles enhanced rebinding of the 33-kDa protein to the particles. 相似文献
2.
Thylakoids and Photosystem II particles prepared from the cyanobacterium Synechococcus PCC 7942 washed with a HEPES/glycerol buffer exhibited low rates of light-induced oxygen evolution. Addition of either Ca2+ or Mg2+ to both thylakoids and Photosystem II particles increased oxygen evolution independently, maximal rates being obtained by addition of both ions. If either preparation was washed with NaCl, light induced O2 evolution was completely inhibited, but re-activated in the same manner by Ca2+ and Mg2+ but to a lower level. In the presence of Mg2+, the reactivation of O2 evolution by Ca2+ allowed sigmoid kinetics, implying co-operative binding. The results are interpreted as indicating that not only Ca2+, but also Mg2+, is essential for light-induced oxygen evolution in thylakoids and Photosystem II particles from Synechococcus PC 7942. The significance of the reactivation kinetics is discussed. Reactivation by Ca2+ was inhibited by antibodies to mammalian calmodulin, indicating that the binding site in Photosystem II may be analogous to that of this protein.Abbreviation HEPES
n-2-Hydroxyethylpiperazine--2-ethane sulphonic acid 相似文献
3.
Photosystem II particles were prepared from spinach chloroplasts with Triton X-100, and treated with 1.0 M NaCl to remove polypeptides of 24 kDa and 18 kDa and to reduce the photosynthetic oxygen-evolution activity by about half. Oxygen-evolution activity was restored almost to the original level with 10 mM Ca2+, in a similar manner to the rebinding of 24-kDa polypeptide. Other cations such as magnesium, sodium and manganese ions could not restore any oxygen-evolution activity. These observations, together with a kinetic analysis, suggest that Ca2+ can be substituted for the 24-kDa polypeptide in photosynthetic oxygen evolution in Photosystem II particles. 相似文献
4.
《BBA》1985,808(2):231-234
We have studied the conditions required to reactivate oxygen evolution in NaCl-washed Photosystem-II particles. Restoration of oxygen evolution by Ca2+ revealed an heterogeneity in these Photosystem-II particles: 30% possess a low affinity site for Ca2+ (1–2 mM), 70% a high affinity site for Ca2+ (50–100 μM), even in the absence of the 24 kDa protein. The sole effect of the 24 kDa protein added back to Photosystem-II particles shortly before illumination was to stabilize oxygen evolution. Added back more than half an hour before, to Photosystem II particles at a high chlorophyll concentration, it increased oxygen evolution from approx. 40% of the control to 60–70% of the control. After reconstitution, an appreciable fraction of the low-affinity site for Ca2+ was still present. 相似文献
5.
《BBA》1985,807(1):64-73
Photosystem II (PS II) particles retaining a high rate of O2 evolution were prepared from a thermophilic cyanobacterium, Synechococcus vulcanus Copeland, and the composition and properties of their peripheral proteins were investigated. The following results were obtained. (1) The O2-evolving PS II particles of S. vulcanus contained only one peripheral protein with a molecular mass of 34000 which corresponded to the 33 kDa protein in higher plant PS II particles, but no other peripheral proteins corresponding to the 24 and 16 kDa proteins of higher plant PS II particles. (2) The cyanobacterial peripheral 34 kDa protein was removed from the particles by 1 M CaCl2-washing concomitant with total inactivation of O2 evolution, and the inactivated O2 evolution was reconstituted to 75% of the original activity by rebinding of this protein back to the washed particles. (3) The cyanobacterial peripheral 34 kDa protein rebound to CaCl2-washed spinach PS II particles and restored O2 evolution to an appreciable extent (28%). (4) The spinach peripheral 33 kDa protein rebound to CaCl2-washed PS II particles of S. vulcanus and partially restored O2 evolution (60%). These results suggested that the peripheral 34 kDa protein of S. vulcanus possesses the determinants for both binding and activity reconstitution identical with those of the peripheral 33 kDa protein of spinach. 相似文献
6.
The presence of Ca2+ causes a twentyfold or greater increase in the rate of oxygen evolution by cell-free preparations of Phormidium luridum. The requirement for Ca2+ is specific; other divalent cations are much less effective or are inhibitory. The rate of the Hill reaction is maximal at 30 mM CaCl2 in both detergent-free and Brij 35 preparations. The 3-(3,4-dichlorophenyl)-1,1-dimethylurea-insensitive component of oxygen-evolving activity in each preparation also shows the requirement for added Ca2+. This indicates that Ca2+ is acting close to the oxygen-evolving reaction center of Photosystem II. Defatted bovine serum albumin increases the rate of oxygen evolution in the detergent-free preparation, but does not compete with Ca2+, discounting fatty acid mediation of the effects of Ca2+. Neither excess Hill acceptor nor uncouplers of photophosphorylation diminish the stimulatory effects of Ca2+. 相似文献
7.
《BBA》1987,890(1):66-76
Laser-flash-induced absorption changes at 830 nm, fluorescence-induction curves and the average oxygen yield per flash have been measured in spinach Photosystem II membrane fragments as a function of trypsin treatment and its modification by CaCl2. The following was found. (i) The relative contribution of the nanosecond relaxation to the overall decay kinetics of 830 nm absorption changes reflecting the P-680+-reduction decreases as a function of incubation time with trypsin. Simultaneously, mild treatment at pH = 6.0 markedly increases the extent of 200 μs kinetics that highly revert back to nanosecond kinetics by CaCl2 addition. After harsher trypsin treatment (pH = 7.5) pH-dependent 2–20 μs kinetics appear that cannot be reverted to nanosecond kinetics by CaCl2. (ii) The CaCl2-induced restoration of nanosecond kinetics is mainly due to a Ca2+-induced effect rather than to a functional role of Cl−. Sr2+ can substantially substitute for Ca2+, whereas Mg2+, Mn2+ and monovalent ions are almost inefficient. (iii) A quantitative correlation between the extent of the nanosecond kinetics and the average oxygen yield per flash was not observed. (iv) If CaCl2 is present in the assay medium for trypsin treatment the samples are markedly protected to proteolytic degradation. This effect mainly refers to the reaction pattern of the acceptor side. Other bivalent cations can substitute Ca2+ for its protective function. (v) The CaCl2-induced protection to proteolytic attack is extremely sensitive to a very short trypsin pretreatment that does hardly affect the shape of the fluorescence induction curve. The results are discussed in relation to the functional and structural organization of Photosystem II. 相似文献
8.
《BBA》1985,807(2):127-133
Heat inactivation of oxygen evolution by isolated Photosystem II particles was accelerated by Cl− depletion and exogenous Mn2+. Weak red light also accelerated heat inactivation. Heat treatment released the 33, 24 and 18 kDa proteins and Mn from the Photosystem II particles. The protein release was stimulated by Cl− depletion and exogenous Mn2+, and the Mn release was also stimulated by Cl− depletion. A 50% loss of Mn corresponded to full inactivation of oxygen evolution, whereas no direct correlation seemed to exist between the loss of any one protein and inactivation of oxygen evolution. Removal of the 24 and 18 kDa proteins from photosystem II particles only slightly decreased the heat stability of oxygen evolution. 相似文献
9.
Abdur Rashid Michelle Bernier Leroy Pazdernick Robert Carpentier 《Photosynthesis research》1991,30(2-3):123-130
The inhibitory effect of Zn2+ on photosynthetic electron transport was investigated in native and CaCl2-treated (depleted in extrinsic polypeptides) Photosystem II (PS II) submembrane preparations. Inhibition of 2,6-dichlorophenolindophenol photoreduction by Zn2+ was much stronger in protein-depleted preparations in comparison to the native form. It was found that Ca2+ significantly reduced the inhibition in the native PS II preparations, as did Mn2+ in a combination with H2O2 in the protein-depleted counterparts. No other tested monovalent or divalent cations could replace Ca2+ or Mn2+ in the respective experiments. Diphenylcarbazide could partially relieve (40–45%) the inhibition in both types of preparations. The above indicates the presence of an active Zn2+ inhibitory site on the donor side of PS II. However, neither Ca2+ nor Mn2+ could completely prevent inhibition by high concentrations of Zn2+ (>1 mM). We propose that elevated levels of Zn2+ strongly perturb the conformation of the PS II core complex and might also affect the acceptor side of the photosystem.Abbreviations PMSF
phenylmethanesulfonyl fluoride
- MES
2-(N-morpholino)ethane sulphonic acid
- Chl
chlorophyll
- PS II
Photosystem II
- DCIP
2,6-dichlorophenolindophenol
- DPC
sym-diphenylcabazide
- DCBQ
2,5-dichlorobenzoquinone 相似文献
10.
The reconstitution of high O2 evolution in CaCl2-treated PS II particles was achieved by the simultaneous addition of the 17-, 23- and 34-kDa proteins and total thylakoid lipids in the presence of 25% glycerol and 15 mM sodium cholate. The activity of the reconstituted membranes recovered to 85% of that of the non-depleted original PS II particles at the optimal condition. By means of this reconstitution method, evidence for the cooperation of the three proteins in the recovery of O2 evolution in the CaCl2-treated PS II particles was found by changing the concentration of NaCI in the assay medium, and the relationship between the amount of manganese retained in the water-splitting complex and the O2 evolving activity was examined by using the partially solubilized PS II particles with n-octyl-β-D-glucoside. 相似文献
11.
Control of Ca2+ efflux and cyclic AMP by 5-hydroxytryptamine and dopamine in abalone gill. 总被引:1,自引:0,他引:1
5-Hydroxytrptamine increased the rate of Ca2+ efflux and the concentration of endogenous cyclic AMP in abalone gill in both 10 mM and 50 mM CaCl2 concentrations externally. Dopamine decreased the rate of Ca2+ efflux in 50 mM CaCl2 but slightly increased the efflux rate in 10 mM CaCl2. At both external Ca2+ concentrations, dopamine increased the endogenous cyclic AMP concentration in the gill. 5-Hydroxytryptamine but not dopamine was found to activate adenylate cyclase in broken cell preparations of abalone gill. Cyclic AMP-dependent protein kinase activity was also demonstrated in homogenate fractions of abalone gill. It is suggested that both Ca2+ and cyclic AMP act as second messengers in the response of abalone gill to 5-hydroxytryptamine and dopamine. 相似文献
12.
《Plant Physiology and Biochemistry》1999,37(7-8):569-576
Two tomato (Lycopersicon esculentum Mill.) lines differing in Ca2+ use efficiency (Ca2+ use efficient line 113 and Ca2+ use inefficient line 67) were subjected to salinity treatments in two separate experiments to determine whether they differed in salt tolerance. In experiment I, three NaCl and two CaCl2 treatments were imposed. The Na+ concentrations were 1.1, 100 and 150 mM and the Ca2+ concentrations were either 1.51 or 10 mM. In experiment II, one NaCl and three Ca2+ treatments (as CaCl2 or CaSO4) were imposed. The treatments consisted of 150 mM NaCl at either 1.51 mM CaCl2, 10 mM CaCl2, or 10 mM CaSO4. Response to treatments was determined by analysis of growth parameters (shoot and root dry weights, plant height, and root length). Shoot and root dry weight, and root length were depressed as salinity increased in plants lacking additional Ca2+. No significant differences in salt tolerance were detected between the two tomato lines after 24 d of salinity treatment. An important finding of this study was that root growth and length appeared to be more sensitive to the effect of CaCI2 treatment alone and to the effects of CaCl2 × NaCl treatments. This suggests that over the long term, both root growth and root length may be more sensitive indicators of salinity effects than shoots. Supplemental CaCl2 had no ameliorative effect on NaCl stress in shoot growth. The inability of Ca2+ to counter Cl− entry or toxicity may account for the lack of amelioration. Additional Ca2+ as CaSO4 improved shoot growth of plants exposed to 150 mM NaCl. In contrast, root growth and length were improved by 10 mM Ca2+ as either CaCl2 or CaSO4. 相似文献
13.
Extraction with EDTA of lyophilized and lysozyme treated preparations of the blue-green algae Anacystis nidulans resulted in loss of the capacity for photoevolution of O2. Reactivation was achieved by the addition of both cations: Mn2+ and Ca2+ (or to a smaller extent by Mn2+ and Sr2+). The dual requirement for Mn2+ and Ca2+ could be demonstrated when the O2 evolution under short saturating light flashes and the variable chlorophyll fluorescence associated with the reduction of the primary acceptor of Photosystem II was examined. The fluorescence experiments in addition showed that incorporation of the cations was a light dependent step, since the fluorescence rise only started after a lag period. 相似文献
14.
Photosystem (PS) II particles prepared from spinach thylakoids with Triton X-100 were treated with 1.5 M NaCl either in the light or dark. Under both conditions, the 24-kDa and 18-kDa proteins were released from the particles, but rebound to them when the NaCl concentration was reduced to 34 mM by dilution. Oxygen evolution measured after the dilution was inactivated following NaCl treatment in the light, but not following treatment in the dark. The inactivation in the light was suppressed when 5 mM CaCl2 was added during or after the NaCl treatment. Based on these observations, a scheme is proposed for the mechanism of light-dependent inactivation of oxygen evolution during NaCl treatment of PS II particles and for the function of the 24-kDa protein in regulating the conformation of a supposed Ca2+-binding intrinsic protein.Abbreviations Chl
chlorophyll
- EGTA
ethyleneglycol-bis-(-aminoethyl ether)-N,N,N,N-tetraacetic acid
- Mes
4-morpholineethanesulphonic acid
- PS
photosystem
- SDS
sodium dodecylsulphate 相似文献
15.
Ajmalicine production in methyl jasmonate-induced Catharanthus roseus cell cultures depends on Ca2+ level 总被引:1,自引:0,他引:1
Cytosolic Ca2+ and jasmonate mediate signals that induce defense responses in plants. In this study, the interaction between Ca2+ and methyl jasmonate (MJ) in modulating defense responses was investigated by monitoring ajmalicine production in Catharanthus roseus suspension cultures. C. roseus suspensions were treated with nine combinations of CaCl2 (3, 23, and 43 mM) and MJ (0, 10, and 100 μM) on day 6 of growth. Increased Ca2+ influx through the addition of extracellular CaCl2 suppressed ajmalicine production in MJ-induced cultures. The highest ajmalicine production (4.75 mg/l) was observed when
cells were treated with a low level of calcium (3 mM) combined with a high level of MJ (100 μM). In the presence of 3 mM CaCl2 in the medium, the addition of Ca2+ chelator EGTA (1, 2.5, and 5 mM) or Ca2+ channel blocker verapamil (1, 10, and 50 μM) to MJ-induced (100 μM) cultures on day 6 also inhibited ajmalicine production
at higher levels of the Ca2+ inhibitors. Hence, ajmalicine production in MJ-induced C. roseus cultures depended on the intracellular Ca2+ concentration and a low extracellular Ca2+ concentration (3 mM) enhanced MJ-induced ajmalicine production. 相似文献
16.
《BBA》1985,808(3):353-362
Various approaches have been used to investigate the polypeptides required for oxygen evolution in cyanobacteria, in particular the thermophile Phormidium laminosum. Antibodies against the extrinsic 33 kDa protein from spinach Photosystem II cross-reacted clearly in immunoblotting experiments with a corresponding polypeptide in isolated thylakoids and Photosystem II particles from P. laminosum and with whole-cell homogenates of three species of cyanobacteria (Phormidium laminosum, Synechococcus leopoliensis and Anabaena variabilis). In contrast, no cyanobacterial proteins reacted with antibodies against the 23 and 16 kDa proteins of spinach Photosystem II. The lack of cross-reactivity and the absence of these polypeptides from highly active Photosystem II particles of Phormidium laminosum strongly suggest that cyanobacteria do not contain polypeptides corresponding to these two chloroplast proteins. Treatment of P. laminosum Photosystem II particles with 0.8 M alkaline Tris, 1 M NaCl, CaCl2 or MgCl2 inhibited O2 evolution, and quantitatively removed a 9 kDa polypeptide from the particles. None of these treatments removed comparable amounts of the 33 kDa polypeptide, and only Tris treatment removed manganese. The release of the 9 kDa polypeptide upon NaCl treatment correlated well with the deactivation at the donor side of Photosystem II. A direct connection between the 33 kDa polypeptide and O2 evolution was established by the finding that trypsin treatment digested this polypeptide and inhibited O2 evolution in parallel. 相似文献
17.
Maria Rova Lars-Gunnar Franzén Per-Olof Fredriksson Stenbjörn Styring 《Photosynthesis research》1994,39(1):75-83
The psbP gene product, the so called 23 kDa extrinsic protein, is involved in water oxidation carried out by Photosystem II. However, the protein is not absolutely required for water oxidation. Here we have studied Photosystem II mediated electron transfer in a mutant of Chlamydomonas reinhardtii, the FUD 39 mutant, that lacks the psbP protein. When grown in dim light the Photosystem II content in thylakoid membranes of FUD 39 is approximately similar to that in the wild-type. The oxygen evolution is dependent on the presence of chloride as a cofactor, which activates the water oxidation with a dissociation constant of about 4 mM. In the mutant, the oxygen evolution is very sensitive to photoinhibition when assayed at low chloride concentrations while chloride protects against photoinhibition with a dissociation constant of about 5 mM. The photoinhibition is irreversible as oxygen evolution cannot be restored by the addition of chloride to inhibited samples. In addition the inhibition seems to be targeted primarily to the Mn-cluster in Photosystem II as the electron transfer through the remaining part of Photosystem II is photoinhibited with slower kinetics. Thus, this mutant provides an experimental system in which effects of photoinhibition induced by lesions at the donor side of Photosystem II can be studied in vivo.Abbreviations Chl
chlorophyll
- DCIP
2,6-dichlorophenolindophenol
- DPC
2,2-diphenylcarbonic dihydrazide
- HEPES
4-(2-hydroxyethyl)-1-piperazinethanesulfonic acid
- P680
the primary electron donor to PS II
- PpBQ
phenyl-p-benzoquinone
- PS II
Photosystem II
- QA
the first quinone acceptor of PS II
- QB
the second quinone acceptor of PS II
- SDS
sodium dodecyl sulfate
- Tris
tris(hydroxymethyl)aminomethane
- TyrD
accessory electron donor on the D2-protein
- TyrZ
tyrosine residue, acting as electron carrier between P680 and the water oxidizing system 相似文献
18.
Treatment of Photosystem II particles from spinach chloroplasts with Triton X-100 with 2.6 M urea in the presence of 200 mM NaCl removed 3 polypeptides of 33 kDa, 24 kDa and 18 kDa, but left Mn bound to the particles. The (urea + NaCl)-treated particles could evolve oxygen in 200 mM, but not in 10 mM NaCl. Mn was gradually released with concomitant loss of oxygen-evolution activity in 10 mM NaCl but not in 200 mM Cl?. The NaCl-treated particles, which contained Mn and the 33-kDa polypeptide but not the 24-kDa and 18-kDa polypeptides, did not lose Mn or oxygen-evolution activity in 10 mM NaCl. These observations suggest that the 33-kDa polypeptide maintains the binding of Mn to the oxygen-evolution system and can be functionally replaced by 200 mM Cl?. 相似文献
19.
Suleyman I. Allakhverdiev Hidenori Hayashi Yoko Fujimura Vyacheslav V. Klimov Norio Murata 《Photosynthesis research》1993,35(3):345-349
We examined the effects of o-phenanthroline and LiClO4 on oxygen evolution and electron transport in the Photosystem 2 complex of the pea. Treatment of Photosystem 2 particles with a combination of 3.0 mM o-phenanthroline and 1.0 M LiClO4 for 30–40 min at 0°C decreased the oxygen-evolving activity with the electron acceptor (either phenyl-p-benzoquinone or 2,6-dichlorophenol indophenol) to less than 5% of the original level. However with the same treatment, the electron-transport activity from an artificial electron donor, 1,5-diphenylcarbohydrazide, to 2,6-dichlorophenol indophenol remained at 60% of the original activity. The amount of manganese in the Photosystem 2 complex decreased in parallel with the loss of oxygen evolution following treatment. These observations suggest that the treatment of the Photosystem 2 complex with o-phenanthroline and LiClO4 inhibits electron transport on the oxygen-evolving side much more significantly than on the electron-acceptor side.Abbreviations Chl
chlorophyll
- DCPIP
2,6-dichlorophenol indophenol
- DPC
1,5-diphenylcarbo hydrazide
- EDTA
ethylenediaminetetraacetic acid
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- Mes
4-morpholineethanesulfonic acid
- PBQ
phenyl-p-benzoquinone
- PS 2
Photosystem 2 相似文献
20.
Delayed light emission from the Triton-fractionated Photosystem II subchloroplast fragments (TSF-IIa) was measured between 0.5 and 10 ms after the termination of illumination. The delayed light emission was diminished by Photosystem II inhibitors, DCMU and o-phenanthroline, which act between the reduced primary acceptor and the plastoquinone pool.Secondary electron donors to Photosystem II, diphenylcarbazide, phenylenediamine, Mn2+, and ascorbate inhibited delayed light emission. Secondary electron acceptors such as ferricyanide, dichlorophenol indophenol, and dimethyl benzoquinone enhanced delayed light emission. The addition of secondary electron acceptors to TSF-IIa particles containing Mn2+ restored delayed light emission to almost the control level. The plastoquinone antagonist, 2,5-dibromo-3-methyl-6-isopropyl p-benzoquinone, increased delayed light emission at low concentrations but decreased it at higher concentrations. Silicomolybdate enhanced the delayed light emission of TSF-IIa particles markedly, and reversed the inhibition by DCMU. Silicomolybdate showed a similar stimulatory effect on the delayed-light intensity in broken spinach chloroplasts at shorter times after the termination of illumination. Carbonyl cyanide m-chloro (or p-trifluoromethoxy) phenylhydrazones inhibited the delayed light emission, but NH4Cl had no effect. 相似文献