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1.
Selective extraction-reconstitution experiments with the extrinsic Photosystem II polypeptides (33 kDa, 23 kDa and 17 kDa) have demonstrated that the manganese complex and the 33 kDa polypeptide are both necessary structural elements for the tight binding of the water soluble 17 and 23 kDa species. When the manganese complex is intact the 33 kDa protein interacts strongly with the rest of the photosynthetic complex. Destruction of the Mn-complex has two dramatic effects: i) The binding of the 33 kDa polypeptide is weaker, since it can be removed by exposure of the PS II system to 2 M NaCl, and ii) the 17 and 23 kDa species do not rebind to Mn-depleted Photosystem II membranes that retain the 33 kDa protein.Abbreviations Chl
chlorophyll
- HQ
hydroquinone
- MES
2(N-morpholino)ethanesulfonic acid
- PS II
Photosystem II
- Tris
2-amino-2-hydroxymethylpropane-1,3-diol 相似文献
2.
Removal of 23 and 17 kDa water-soluble polypeptides from PS II membranes causes a marked decrease in oxygen-evolution activity, exposes the oxidizing side of PS II to exogenous reductants (Ghanotakis, D.F., Babcock, G.T. and Yocum, C.F. (1984) Biochim. Biophys. Acta 765, 388–398) and alters a high-affinity binding site for Ca2+ in the oxygen-evolving complex (Ghanotakis, D.F., Topper, J.N., Babcock, G.T. and Yocum, C.F. (1984) FEBS Lett. 170, 169–173). We have examined further the state of the functional Mn complex in PS II membranes from which the 17 and 23 kDa species have been removed by high-salt treatment. These membranes contain a structurally altered Mn complex which is sensitive to destruction by low concentrations of NH2OH which cannot, in native PS II membranes, cause extraction of functional Mn. In addition to NH2OH, a wide range of other small (H2O2, NH2NH2, Fe2+) and bulky (benzidine, hydroquinone) electron donors extract Mn (up to 80%) from the polypeptide-depleted PS II preparations. This extraction is due to reduction of the functional Mn complex since light, which would generate higher oxidation states within the Mn complex, prevents Mn release by reductants. Release of Mn by reductants does not extract the 33 kDa water-soluble protein implicated in Mn binding to the oxidizing side of PS II, although the protein can be partially or totally extracted from Mn-depleted preparations by exposure to high ionic strength or to high (0.8 M) concentrations of Tris. We view our results as evidence for a shield around the Mn complex of the oxygen-evolving complex comprised of the 33 kDa polypeptide along with the 23 and 17 kDa proteins and tightly bound Ca2+. 相似文献
3.
Three extrinsic polypeptides and manganese cluster were sequentially released from the membrane when photosystem 2 (PS2) membranes were kept under high hydrostatic pressure. The 17 kDa polypeptide was the most sensitive, while the 33 kDa polypeptide was the most reluctant to the treatment with high pressure. The release of manganese was not simply correlated with the loss of 33 kDa polypeptide. The losing of oxygen-evolving activity of PS2 was synchronised with the releasing of extrinsic polypeptides and manganese. 相似文献
4.
Eric Lam Barbara Baltimore William Ortiz Susan Chollar Anastasios Melis Richard Malkin 《BBA》1983,724(2):201-211
An oxygen-evolving Photosystem (PS) II preparation was isolated after Triton X-100 treatment of spinach thylakoids in the presence of Mg2+. The structural and functional components of this preparation have been identified by SDS-polyacrylamide gel electrophoresis and sensitive spectrophotometric analysis. The main findings were: (1) The concentration of the primary acceptor Q of PS II was 1 per 230 chlorophyll molecules. (2) There are 6 to 7 plastoquinone molecules associated with a ‘quinone-pool’ reducible by Q. (3) The only cytochrome present in significant amounts (cytochrome b-559) occurred at a concentration of 1 per 125 chlorophyll molecules. (4) The only kind of photochemical reaction center complex present was identified by fluorescence induction kinetic analysis as PS IIα. (5) An Em = ? 10 mV has been measured at pH 7.8 for the primary electron acceptor Qα of PS IIα. (6) With conventional SDS-polyacrylamide gel electrophoresis, the preparation was resolved into 13 prominent polypeptide bands with relative molecular masses of 63, 55, 51, 48, 37, 33, 28, 27, 25, 22, 15, 13 and 10 kDa. The 28 kDa band was identified as the PS II light-harvesting chlorophyll . In the presence of 2 M urea, however, SDS-polyacrylamide gel electrophoresis showed seven prominent polypeptides with molecular masses of 47, 39, 31, 29, 27, 26 and 13 kDa as well as several minor components. CP I under identical conditions had a molecular mass of 60–63 kDa. 相似文献
5.
An immunological approach was used for nearest-neighbor analyses for the 23 and 33 kDA proteins of the oxygen-evolving complex. Functional Photosystem II particles with a simple polypeptide composition were partly solubilized with detergent and incubated with monospecific antibodies against either the 23 or the 33 kDa protein. SDS-polyacrylamide gel electrophoresis revealed that the immunoprecipitates, apart from the antigenic proteins, also contained polypeptides at 24, 22 and 10 kDa. In contrast, polypeptides of the light-harvesting and Photosystem II core complexes showed very poor coprecipitation with the 23 and 33 kDa proteins. The 24, 22 and 10 kDa polypeptides were not precipitated by the antibodies if the 23 and 33 kDa proteins had been removed from the particles prior to solubilization. These observations demonstrate a close association between the 24, 22 and 10 kDa polypeptides and the 23 and 33 kDa proteins of the oxygen-evolving complex. None of these precipitated polypeptides contained any manganese. It is suggested that the 24, 22 and 10 kDa polypeptides are subunits of the oxygen-evolving complex and involved in the binding of the extrinsic 23 and 33 kDa proteins to the inner thylakoid surface. 相似文献
6.
《BBA》1985,808(1):171-179
The effects of selective removal of extrinsic proteins on donor side electron transport in oxygen-evolving PS II particles were examined by monitoring the decay time of the EPR signal from the oxidized secondary donor, Z+, and the amplitude of the multiline manganese EPR signal. Removal of the 16 and 24 kDa proteins by washing with 1 M NaCl inhibits oxygen evolution, but rapid electron transfer to Z+ still occurs as evidenced by the near absence of Signal IIf. The absence of a multiline EPR signal shows that NaCl washing induces a modification of the oxygen-evolving complex which prevents the formation of the S2 state. This modification is different from the one induced by chloride depletion of PS II particles, since in these a large multiline EPR signal is found. After removal of the 33 kDa protein with 1 M MgCl2, Signal IIf is generated after a light flash. Readdition of the 33 kDa component to the depleted membranes accelerates the reduction of Z+. Added calcium ions show a similar effect. These findings suggest that partial advancement through the oxygen-evolving cycle can occur in the absence of the 16 and 24 kDa proteins. The 33 kDa protein, on the other hand, may be necessary for such reactions to take place. 相似文献
7.
Curtis W. Hoganson Demetrios F. Ghanotakis Gerald T. Babcock Charles F. Yocum 《Photosynthesis research》1989,22(3):285-293
Manganese in the oxygen-evolving complex is a physiological electron donor to Photosystem II. PS II depleted of manganese may oxidize exogenous reductants including benzidine and Mn2+. Using flash photolysis with electron spin resonance detection, we examined the room-temperature reaction kinetics of these reductants with Yz
+, the tyrosine radical formed in PS II membranes under illumination. Kinetics were measured with membranes that did or did not contain the 33 kDa extrinsic polypeptide of PS II, whose presence had no effect on the reaction kinetics with either reductant. The rate of Yz
+ reduction by benzidine was a linear function of benzidine concentration. The rate of Yz
+ reduction by Mn2+ at pH 6 increased linearly at low Mn2+ concentrations and reached a maximum at the Mn2+ concentrations equal to several times the reaction center concentration. The rate was inhibited by K+, Ca2+ and Mg2+. These data are described by a model in which negative charge on the membrane causes a local increase in the cation concentration. The rate of Yz
+ reduction at pH 7.5 was biphasic with a fast 400 s phase that suggests binding of Mn2+ near Yz
+ at a site that may be one of the native manganese binding sites.Abbreviations PS II
Photosystem II
- YD
tyrosine residue in Photosystem II that gives rise to the stable Signal II EPR spectrum
- Yz
tyrosine residue in Photosystem II that mediates electron transfer between the reaction center chlorophyll and the site of water oxidation
- ESR
electron spin resonance
- DPC
diphenylcarbazide
- DCIP
dichlorophenolindophenol 相似文献
8.
The linear, four-step oxidation of water to molecular oxygen by photosystem II requires cooperation between redox reactions driven by light and a set of redox reactions involving the S-states within the oxygen-evolving complex. The oxygenevolving complex is a highly ordered structure in which a number of polypeptides interact with one another to provide the appropriate environment for productive binding of cofactors such as manganese, chloride and calcium, as well as for productive electron transfer within the photoact. A number of recent advances in the knowledge of the polypeptide structure of photosystem II has revealed a correlation between primary photochemical events and a core complex of five hydrophobic polypeptides which provide binding sites for chlorophyll a, pheophytin a, the reaction center chlorophyll (P680), and its immediate donor, denoted Z. Although the core complex of photosystem II is photochemically active, it does not possess the capacity to evolve oxygen. A second set of polypeptides, which are water-soluble, have been discovered to be associated with photosystem II; these polypeptides are now proposed to be the structural elements of a special domain which promotes the activities of the loosely-bound cofactors (manganese, chloride, calcium) that participate in oxygen evolution activity. Two of these proteins (whose molecular weights are 23 and 17 kDa) can be released from photosystem II without concurrent loss of functional manganese; studies on these proteins and on the membranes from which they have been removed indicate that the 23 and 17 kDa species from part of the structure which promotes retention of chloride and calcium within the oxygen-evolving complex. A third water-soluble polypeptide of molecular weight 33 kDa is held to the photosystem II core complex by a series of forces which in some circumstances may include ligation to manganese. The 33 kDa protein has been studied in some detail and appears to promote the formation of the environment which is required for optimal participation by manganese in the oxygen evolving reaction. This minireview describes the polypeptides of photosystem II, places an emphasis on the current state of knowledge concerning these species, and discusses current areas of uncertainty concerning these important polypeptides.Abbreviations A 23187
ionophore that exchanges divalent cations with H+
- Chl
chlorophyll
- cyt
cytochrome
- DCPIP
dichlorophenolindophenol
- DPC
diphenylcarbazide
- EGTA
ethyleneglycoltetraacetic acid
- P680
the chlorophyll a reaction center of photosystem II
- pheo
pheophytin
- PQ
plastoquinone
- PS
photosystem
- QA and QB
primary and secondary plastoquinone electron acceptors of photosystem II
- Sn (n=0, 1, 2, 3, 4)
charge accumulating state of the oxygen evolving system
- Signals IIvf, IIf and IIs
epr-detectable free radicals associated with the oxidizing side of photosystem II
- Z
primary electron donor to the photosystem II reaction center
The survey of literature for this review ended in September, 1984. 相似文献
9.
The effect of linolenic acid (18:3) on release of the 43 kDa polypeptide and manganese from photosystem II ( PS II ) membranes depleted of extrinsic polypeptides was studied. In both control and NaCl-washed particles which were depleted of the extrinsic 23 and 16 kDa polypeptides, the 18:3 treatment caused a 20% release of the 33 and 43 kDa polypeptides. In CaCl2 , (or urea + NaCl)-washed particles, which were depleted of the 33 kDa polypeptide in addition to the 23 and 16 kDa polypeptides, the release of the 43 kDa polypeptide increased to 70%, whereas only 25% of the 47 kDa polypeptide was removed. These findings suggest (i) that the 33 and the 43 kDa polypeptides are neighbows in the photosynthetic membrane and (ii) that the 33 kDa polypeptide shields the 43 kDa polypeptide against the action of 18:3. Incubation of CaCl2 , or (urea + NaCI)-treated PSII particles in the presence or absence of 18:3 resulted in the loss of only 2 of the 4 Mn atoms present per reaction center. this indicates that the 2 Mn atoms more firmly associated with PSII are not affected by the removal of the extrinsic 16, 23 and 33 kDa polypeptides, and the intrinsic 43 kDa polypeptide. nor by the treatment with linolenic acid. 相似文献
10.
Christer Jansson Örjan Hansson Hans-Erik Åkerlund Lars-Erik Andreasson 《Biochemical and biophysical research communications》1984,124(1):269-276
EPR measurements on inside-out thylakoids revealed that salt-washing, known to inhibit oxygen evolution and release a 23 and a 16 kDa protein, induced a Signal IIf and decreased the EPR signal from state S2. Readdition of the released 23 kDa protein restored the oxygen evolution and decreased the Signal IIf, but did not relieve the decrease in the state S2 signal. It is suggested that salt-washing inhibits the electron transfer from the oxygen-evolving site to Z, the physiological donor to P680. In inhibited photosystem II units lacking Signal IIf, Z+ is rapidly reduced, possibly by a modified S-cycle unable to evolve oxygen. 相似文献
11.
The kinetics of the S-state transitions of the oxygen-evolving complex were analyzed in dark-adapted, oxygen-evolving Photosystem-II preparations supplied with the electron acceptor 2,5-dichloro-p-benzoquinone. The kinetics of flash-induced absorbance changes at 350 nm, largely due to the successive S-state transitions S0 → S1, S1 → S2, S2 → S3 and S3 →; S0, confirm the +1, +1, +1, ?3 sequence of manganese oxidation reported earlier (Dekker, J.P., Van Gorkom, H.J., Wensink, J. and Ouwehand, L. (1984) Biochim. Biophys. Acta 767, 1–9), and reveal half-times of 30, 110, 350 and 1300 μs, respectively, for these transitions. 相似文献
12.
Kashino Yasuhiro; Enami Isao; Igarashi Sahoko; Katoh Sakae 《Plant & cell physiology》1992,33(3):259-266
Oxygen-evolving photosystem II (PS II) particles isolated fromthe thermophilic cyanobacterium Synechococcus elongatus consistedof about twenty polypeptides. Six polypeptides were identifiedby reaction with specific antisera as constituent subunit polypeptidesof oxygen-evolving PS II reaction center complexes. The mostabundant polypeptides were the and ß subunits ofallophycocyanin. Comparison with the polypeptide profile ofisolated phycobilisomes, as well as immunoblotting with an antiserumagainst the large linker polypeptide, showed that the largelinker polypeptide or some proteolytic fragments of it werepresent in the preparation. Thus, each PS II particle is, inessence, an oxygen-evolving PS II complex that is associatedwith the core substructure of the phycobilisome. Cross-linkingexperiments indicated that fragments of the large linker polypeptidesare closely associated with one another and that the Chl-carrying47- kDa polypeptide is located in close proximity to the D2protein and the extrinsic 33-kDa protein. (Received November 12, 1991; Accepted January 23, 1992) 相似文献
13.
Phosphorylation in vitro of the light-harvesting chlorophyll protein complex associated with Photosystem II (LHCII) resulted in the lateral migration of a subpopulation of LHCII from the grana to the stroma lamellae. This movement was characterized by a decrease in the chlorophyll ratio and an increase in the 77 K fluorescence emission at 681 nm in the stroma lamellae following phosphorylation. Polyacrylamide gel electrophoresis indicated that the principal phosphoproteins under these conditions were polypeptides of 26–27 kDa. These polypeptides increased in relative amount in the stroma lamellae and decreased in the grana during phosphorylation. Pulse/chase experiments confirmed that the polypeptides were labelled in the grana and moved to the stroma lamellae in the subsequent chase period. A fraction at the phospho-LHCII, however, was unable to move and remained associated with the grana fraction. LHCII which moved out into the stroma lamellae effectively sensitized Photosystem I (PS I), since the ability to excite fluorescence emission at 735 nm (at 77 K) by chlorophyll b was increased following phosphorylation. These data support the ‘mobile antenna’ hypothesis proposed by Kyle, Staehelin and Arntzen (Arch. Biochem. Biophys. (1983) 222, 527–541) which states that the alterations in the excitation-energy distribution induced by LHCII phosphorylation are, in part, due to the change in absorptive cross-section of PS II and PS I, resulting specifically from the movement of LHCII antennae chlorophylls from the PS-II-enriched grana to the PS-I-enriched stroma lamellae. 相似文献
14.
Deoxycholate was used to solubilize the 16 and 24 kDa polypeptides from spinach thylakoids, resulting in the loss of oxygen evolution. Manganese was retained in the membrane. When the deoxycholate-extracted membranes were subjected to a mild heat treatment, the water-soluble 33 kDa protein was selectively released. Less than one manganese per reaction center was lost on heating but this loss was not correlated to the solubilization of protein. Most of the manganese bound to the membrane remained EPR-undetectable and could be released by 2-amino-2-hydroxymethylpropane-1,3-diol (Tris) or hydroxylamine treatments. This indicates that the manganese involved in oxygen evolution remains in its native binding site despite the loss of the 33 kDa protein. These results contradict the hypothesis that the 33 kDa protein is responsible for manganese binding at the photosynthetic oxygen-evolving site. 相似文献
15.
Three extrinsic proteins (PsbO, PsbP and PsbQ), with apparent molecular weights of 33, 23 and 17 kDa, bind to the lumenal
side of Photosystem II (PS II) and stabilize the manganese, calcium and chloride cofactors of the oxygen evolving complex
(OEC). The effect of these proteins on the structure of the tetramanganese cluster, especially their possible involvement
in manganese ligation, is investigated in this study by measuring the reported histidine-manganese coupling [Tang et al. (1994)
Proc Natl Acad Sci USA 91: 704–708] of PS II membranes depleted of none, two or three of these proteins using ESEEM (electron
spin echo envelope modulation) spectroscopy. The results show that neither of the three proteins influence the histidine ligation
of manganese. From this, the conserved histidine of the 23 kDa protein can be ruled out as a manganese ligand. Whereas the
33 and 17 kDa proteins lack conserved histidines, the existence of a 33 kDa protein-derived carboxylate ligand has been posited;
our results show no evidence for a change of the manganese co-ordination upon removal of this protein. Studies of the pH-dependence
of the histidine–manganese coupling show that the histidine ligation is present in PS II centers showing the S2 multiline EPR signal in the pH-range 4.2–9.5.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
The oxygen evolving complex of photosystem II (PS II) contains three extrinsic polypeptides of approximate molecular weights 16, 23 and 33 kDa. These polypeptides are associated with the roles of Cl-, Ca2+ and Mn2+ in oxygen evolution. We have shown that selective removal of 16 and 23 kDa polypeptides from the above complex by NaCl washing of PS II enriched membrane fragments renders the PS II core complex more susceptible to the herbicide atrazine. On the other hand, when both native and depleted preparations were resupplied with exogenous Ca2+ and Cl-, we obtained a reduction of atrazine inhibition which was much stronger in the depleted preparations than in the native ones. It is concluded that removal of 16 and 23 kDa polypeptides in general, and disorganization of associated Ca2+ and Cl- in particular, enhances atrazine penetration to its sites of action in the vicinity of the PS II complex. The above could be interpreted if we assume a reduced plastoquinone affinity at the QB (secondary plastoquinone electron acceptor) pocket of D1 polypeptide following transmembranous modifications caused by the depletion of these polypeptides.Abbreviations CCCP
carbonylcyanide-m-chlorophenylhydrazone
- Chl
chlorophyll
- DCIP
2,6-dichlorophenolindophenol
- MES
2-(N-morpholino)ethanesulfonic acid
- PMSF
phenylmethylsul-phonyfluoride
- PS II
photosystem II
- PAGE
polyacrilamide gel electrophoresis 相似文献
17.
Pb2+ and Zn2+ inhibition of photosystem II (PSII) activity was reported to be mediated via displacement of native inorganic cofactors (Cl−, Ca2+ and Mn2+) from the oxygen evolving complex, OEC [Rashid and Popovic (1990) FEBS Lett. 271, 181–184; Rashid et al. (1991) Photosynth. Res. 30, 123–130]. Since the binding sites of these cofactors are protected by a shield of three extrinsic polypeptides (17, 23 and 33 kDa), we investigated whether these metal ions affect the extrinsic polypeptide shield of OEC. By immunoblotting with antibodies recognizing the 23 and 33 kDa polypeptides, we showed that both the metal ions significantly dissociated the 23 kDa (+17 kDa) polypeptide, and partially dissociated the 33 kDa. Ca2+, one of the important inorganic cofactors of oxygen evolution, strongly prevented the dissociating action of Pb2+ but did not prevent the action of Zn2+. The probable molecular mechanism of action of Pb2+ and Zn2+ on PSII OEC is discussed. 相似文献
18.
Selective solubilization of Photosystem II membranes with the non-ionic detergent octyl thioglucopyranoside has allowed the isolation of a PS II system which has been depleted of the 22 and 10 kDa polypeptides but retains all three extrinsic proteins (33, 23 and 17 kDa). The PS II membranes which have been depleted of the 22 and 10 kDa species show high rates of oxygen evolution activity, external calcium is not required for activity and the manganese complex is not destroyed by exogenous reductants. When we compared this system to control PS II membranes, we observed a minor modification of the reducing side, and a conversion of the high-potential to the low-potential form of cytochrome b
559.Abbreviations Chl-
chlorophyll
- DCBQ-
2,5-dichloro-p-benzoquinone
- DCMU-
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- ESR-
electron spin resonance
- MES-
2-(N-morpholino)ethanesulfonic acid
- OTG-
octyl--d-thioglucopyranoside
- PS II-
Photosystem II
- PEG-
polyethylene glycol, Mr=6000
- Tris-
2-amino-2-hydroxyethylpropane-1,3-diol 相似文献
19.
D. F. Ghanotakis C. M. Waggoner N. R. Bowlby D. M. Demetriou G. T. Babcock C. F. Yocum 《Photosynthesis research》1987,14(3):191-199
Biochemical techniques now exist to produce the oxygen-evolving complex of photosystem II (PSII) and its associated photochemical redox reactions in various states of purity. These preparations permit one to assess the structural roles of polypeptides in promoting activity by using selective extraction techniques which remove certain polypeptides, to carry out reconstitution studies which re-establish activity, and, in the case of more recently developed, highly purified preparations discussed in this overview, to identify the minimal polypeptide complement necessary for photosynthetic oxygen evolution activity. These comparative investigations also suggest a tentative structure for an oxygen-evolving PSII core complex whose primary constituents are a hydrophobic complex of polypeptide, manganese, calcium and chloride, and the 33 kDa extrinsic polypeptide.Abbreviations DCBQ
2,6 dichloro-p-benzoquinone
- Chl
chlorophyll
- LHCP
light-harvesting chlorophyll proteins
- PS
photosystem
Presented at the Japan/US Binational Seminar on Energy Conversion: Photochemical Reaction Centers and Oxygen-Evolving Complexes of Plant Photosynthesis, March 17–21, 1987. See conference report by G. Renger in Photosynthesis Research, in press, 1987...Editor. 相似文献
20.
Steve Boisvert David Joly Sébastien Leclerc Sridharan Govindachary Johanne Harnois Robert Carpentier 《Biometals》2007,20(6):879-889
The toxic effect of Ni2+ on photosynthetic electron transport was studied in a photosystem II submembrane fraction. It was shown that Ni2+ strongly inhibits oxygen evolution in the millimolar range of concentration. The inhibition was insensitive to NaCl but significantly
decreased in the presence of CaCl2. Maximal chlorophyll fluorescence, together with variable fluorescence, maximal quantum yield of photosystem II, and flash-induced
fluorescence decays were all significantly declined by Ni2+. Further, the extrinsic polypeptides of 16 and 24 kDa associated with the oxygen-evolving complex of photosystem II were
depleted following Ni2+ treatment. It was deduced that interaction of Ni2+ with these polypeptides caused a conformational change that induced their release together with Ca2+ from the oxygen-evolving complex of photosystem II with consequent inhibition of the electron transport activity. 相似文献