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1.
The precursor to the nuclear-coded 17 kDa early light-inducible protein (ELIP) of pea has been transported into isolated intact chloroplasts. The location of the mature protein in the thylakoid membranes was investigated after using cleavable crosslinkers such as DSP and SAND in conjunction with immuno-fractionation methods and by application of mild detergent fractionation. We show that ELIP is integrated into the membranes via the unstacked stroma thylakoids. After isolation of protein complexes by solubilization of membranes with Triton X-100 and sucrose density-gradient centrifugation the crosslinked ELIP comigrates with the PS II core complex. Using SAND we identified ELIP as a 41–51 kDa crosslinked product while with DSP four products of 80 kDa, 70 kDa, 50–42 kDa and 23–21 kDa were found. The immunoprecipitation data suggested that the D1-protein of the PS II complex is one of the ELIP partners in crosslinked products.Abbreviations chl
chlorophyll
- D1
herbicide-binding protein
- DSP
dithiobis-(succinimidylpropionate)
- ELIP
early light-inducible protein
- LHC I and LHC II
light-harvesting chlorophyll a/b complex associated with photosystem I or II
- PAGE
polyacrylamide gel electrophoresis
- poly(A)-rich RNA
polyadenyd mRNA
- PS I and PS II
photosystems I and II
- SAND
sulfosuccinimidyl 2-(m-azido-o-nitro-benzamido)-ethyl-1,3-dithiopropionate
- Triton X-100
octylphenoxypolyethoxyethanol 相似文献
2.
LHC II isolated from carnation leaves has been solubilized and resolved by a newly developed, vertical-bed non-denaturing isoelectric focusing in polyacrylamide slab gels to yield three trimeric subcomplexes focusing at pH 4.52, 4.42 and 4.37 (designated a, b and c, respectively), comprising approximately 38%, 24% and 38% of the chlorophyll. The spectroscopic data demonstrated a close similarity among LHC II subcomplexes concerning their chlorophyll content and organization. The most alkaline and the most acidic subcomplex contained the 27 kDa polypeptide of LHC II while the intermediate pI fraction contained both LHC II polypeptides, i.e. 27 kDa and 26 kDa ones associated at 2:1 stoichiometry. The 27 kDa polypeptide could be resolved by denaturing isoelectrofocusing into 10 pI molecular isoforms covering 5.90–4.20 pH range. Three of the isoforms were found in the subcomplexes a and b and eight in the subcomplex c. The 26 kDa polypeptide comprised the unique pI molecular isoform focusing at pH 5.61.Abbreviations CBB G-250
Coomassie Brilliant Blue G-250
- chl
chlorophyll
- DM
n-dodecyl--d-maltoside
- EDTA
ethylendiaminotetraacetic acid
- IEF
isoelectric focusing
- LHC II
the main light-harvesting chlorophyll a/b-protein complex of Photosystem II
- LHCP II
apoprotein of the main light-harvesting chlorophyll a/b-protein complex of Photosystem II
- NP-40
polyethyleneglycol-p-isooctylphenyl ether
- pI
isoelectric point
- OG
octyl--d-glucopyranoside
- PS II
Photosystem II
- SDS-PAGE
sodium dodecylsulphate polyacrylamide gel electrophoresis
- TCA
trichlorooacetic acid 相似文献
3.
A relative decrease of the high temperature part (above 60°C) of the chlorophyll fluorescence temperature curve during 3 h to 10 h greening period of barley (Hordeum vulgare L.) leaves was found to be concomitant to a decrease of Chl alb ratio and to a gradual increase of LHCP/core ratio found by electrophoresis and the ratio of granal to total length of thylakoid membranes. It is suggested that the high temperature part of the fluorescence temperature curve depends inversely on the relative amount of LHC II in thylakoid membranes.Abbreviations Chl a(b)
chlorophyll a(b)
- CPa
chlorophyll a protein complex of PS II
- CP1
P700 chlorophyll a protein complex of PS I
- FP
free pigments
- FTC
fluorescence temperature curve
- F(T30)
fluorescence intensity at 30°C
- LHC II
light harvesting complex II
- LHCP
light harvesting chlorophyll protein
- LHCP3 (LHCPm)
monomeric form of LHC II
- LHCPo
oligomeric form of LHC II complex
- M1
first maximum of FTC
- M2
second maximum (region) of FTC
- PAA
polyacrylamide
- PAR
photosynthetically active radiation
- PS I(II)
Photosystem I(II)
- SDS-PAGE
sodium dodecyl sulfate polyacrylamide gel electrophoresis 相似文献
4.
The structure and heterogeneity of LHC II were studied by in vitro reconstitution of apoproteins with pigments (Plumley and Schmidt 1987, Proc Natl Acad Sci 84: 146–150). Reconstituted CP 2 complexes purified by LDS-PAGE were subsequently characterized and shown to have spectroscopic properties and pigment-protein compositions and stoichiometries similar to those of authentic complexes. Heterologous reconstitutions utilizing pigments and light-harvesting proteins from spinach, pea and Chlamydomonas reinhardtii reveal no evidence of specialized binding sites for the unique C. reinhardtii xanthophyll loroxanthin: lutein and loroxanthin are interchangeable for in vitro reconstitution. Proteins modified by the presence of a transit peptide, phosphorylation, or proteolytic removal of the NH2-terminus could be reconstituted. Evidence suggests that post-translational modification are not responsible for the presence of six electrophoretic variants of C. reinhardtii CP 2. Reconstitution is blocked by iodoacetamide pre-treatment of the apoproteins suggesting a role for cysteine in pigment ligation and/or proper folding of the pigment-protein complex. Finally, no effect of divalent cations on pigment reassembly could be detected.Abbreviations
cab
chlorophyll a/b-binding protein genes
- Chl
chlorophyll
- CP2
light-harvesting chlorophyll A+b-protein complex fractionated by mildly denaturing LDS-PAGE from Photosystem II in thylakoids
- CP 43 and CP 47
chlorophyll a-antenna complexes fractionated from Photosystem II in thylakoids by mildly denaturing LDS-PAGE at 4°C
- IgG
gamma immunoglobulin
- LDS
lithium dodecyl sulfate
- LDS-PAGE
lithium dodecyl sulfate polyacrylamide gel electrophoresis at 4°C
- LHC I and LHC II
thylakoid light-harvesting chlorophyll a+b-protein holocomplexes associated with Photosystems I and II, respectively
- PS II
Photosystem II
- TX100
Triton X-100
- TX100-derived LHC
light-harvesting complexes enriched in LHC II following fractionation of thylakoids by TX100 相似文献
5.
Consequences of LHC II deficiency for photosynthetic regulation in chlorina mutants of barley 总被引:1,自引:0,他引:1
The light-harvesting chlorophyll a/b proteins associated with PS II (LHC II) are often considered to have a regulatory role in photosynthesis. The photosynthetic responses of four chlorina mutants of barley, which are deficient in LHC II to varying degrees, are examined to evaluate whether LHC II plays a regulatory role in photosynthesis. The efficiencies of light use for PS I and PS II photochemistry and for CO2 assimilation in leaves of the mutants were monitored simultaneously over a wide range of photon flux densities of white light in the presence and absence of supplementary red light. It is demonstrated that the depletions of LHC II in these mutants results in a severe imbalance in the relative rates of excitation of PS I and PS II in favour of PS I, which cannot be alleviated by preferential excitation of PS II. Analyses of xanthophyll cycle pigments and fluorescence quenching in leaves of the mutants indicated that the major LHC II components are not required to facilitate the light-induced quenching associated with zeaxanthin formation. It is concluded that LHC II is important to balance the distribution of excitation energy between PS I and PS II populations over a wide range of photon flux densities. It appears that LHC II may also be important in determining the quantum efficiency of PS II photochemistry by reducing the rate of quenching of excitation energy in the PS II primary antennae.Abbreviations Fm, Fv
maximal and variable fluorescence yields in a light adapted state
- LHC II
light harvesting chlorophyll a/b protein complex associated with PS II
- qp
photochemical quenching
- A820
light-induced absorbance change at 820 nm
- øPSI, øPSII
relative quantum efficiencies of PS I and PS II photochemistry
- øCO2
quantum yield of CO2 assimilation 相似文献
6.
Rapid and simple isolation of pure photosystem II core and reaction center particles from spinach 总被引:2,自引:2,他引:0
Peter J. van Leeuwen Maaike C. Nieveen Erik Jan van de Meent Jan P. Dekker Hans J. van Gorkom 《Photosynthesis research》1991,28(3):149-153
Pure and active oxygen-evolving PS II core particles containing 35 Chl per reaction center were isolated with 75% yield from spinach PS II membrane fragments by incubation with n-dodecyl--D-maltoside and a rapid one step anion-exchange separation. By Triton X-100 treatment on the column these particles could be converted with 55% yield to pure and active PS II reaction center particles, which contained 6 Chl per reaction center.Abbreviations Bis-Tris
bis[2-hydroxyethyl]imino-tris[hydroxymethyl]methane
- Chl
chlorophyll
- CP29
Chl a/b protein of 29 kDa
- Cyt b
559
cytochrome b
559
- DCBQ
2,5-dichloro-p-benzo-quinone
- LHC II
light-harvesting complex II, predominant Chl a/b protein
- MES
2-[N-Morpholino]ethanesulfonic acid
- Pheo
pheophytin
- PS H
photosystem II
- QA
bound plastoquinone, serving as the secondary electron acceptor in PS II (after Pheo)
- SDS
sodiumdodecylsulfate 相似文献
7.
The light-harvesting accessory pigment-protein complex (LHC) with a chlorophyll (Chl) ratio of 1.2 was isolated by treating pea chloroplasts with Triton X-100. The LHC was used to investigate the action of ionic (sodium dodecyl sulfate) and non-ionic (Triton X-100) detergents. By optical methods (absorption and fluorescence spectra, measurements of fluorescence yield, ?, and lifetime, τ) two successive stages of the process were demonstrated, namely (1) interaction between detergent monomers and proteins and (2) solubilization of pigments into detergent micelles, which is facilitated by the presence of salts. The concentration ranges, characteristic of these stages, differ by 1.5–2 orders of magnitude for SDS, but slightly overlap for Triton X-100. At the second stage, certain changes occur in LHC absorption and fluorescence spectra. Several stable states of the LHC were established: (1) an aggregated state formed in the presence of 10 mM MgSO4 with τ ≈ 0.6 ns; (2) the dialyzed LHC with τ ≈ 0.9 ns; (3) the states of the LHC in detergent solution with τ ≈ 2.3, 2.9, 3.4 ns; (4) a 30 kilodalton monomer obtained by SDS-polyacrylamide gel electrophoresis with τ ≈ 4.1 ns. The fluorescence parameters of the LHC states were compared with those of Chl a in detergent micelles (for the micelles τ = 5.6–6.0 ns. The ratio (the criterion for emission heterogeneity) for the LHC in the absence of a detergent was shown to be higher at least by a factor of 3.5 than that for Chl a in the presence of a detergent. Successive additions of the detergent to the LHC cause gradual decrease in the ratio, and for the LHC monomer it reaches practically the same value as for Chl a in detergent micelles. The results are discussed on the basis of the data obtained previously. It is suggested that in vivo LHCs do not form such aggregates as in water solution without a detergent. 相似文献
8.
Deming Tang Ryszard Jankowiak Michael Seibert Gerald J. Small 《Photosynthesis research》1991,27(1):19-29
Low temperature (4.2 K) absorption and hole burned spectra are reported for a stabilized preparation (no excess detergent) of the photosystem II reaction center complex. The complex was studied in glasses to which detergent had and had not been added. Triton X-100 (but not dodecyl maltoside) detergent was found to significantly affect the absorption and persistent hole spectra and to disrupt energy transfer from the accessory chlorophyll a to the active pheophytin a. However, Triton X-100 does not significantly affect the transient hole spectrum and lifetime (1.9 ps at 4.2 K) of the primary donor state, P680*. Data are presented which indicate that the disruptive effects of Triton X-100 are not due to extraction of pigments from the reaction center, leaving structural perturbations as the most plausible explanation. In the absence of detergent the high resolution persistent hole spectra yield an energy transfer decay time for the accessory Chl a QY-state at 1.6 K of 12 ps, which is about three orders of magnitude longer than the corresponding time for the bacterial RC. In the presence of Triton X-100 the Chl a QY-state decay time is increased by at least a factor of 50.Abbreviations PS I
photosystem I
- PS II
photosystem II
- RC
reaction center
- P680, P870, P960
the primary electron donor absorption bands of photosystem II, Rhodobacter sphaeroides, Rhodopseudomonas viridis
- NPHB
nonphotochemical hole burning
- TX
Triton X-100
- DM
Dodecyl Maltoside
- Chl
chlorophyll
- Pheo
pheophytin
- ZPH
ero phonon hole 相似文献
9.
The light harvesting and photosynthetic characteristics of a chlorophyll-deficient mutant of cowpea (Vigna unguilata), resulting from a single nuclear gene mutation, are examined. The 40% reduction in total chlorophyll content per leaf area in the mutant is associated with a 55% reduction in pigment-proteins of the light harvesting complex associated with Photosystem II (LHC II), and to a lesser extent (35%) in the light harvesting complex associated with Photosystem I (LHC I). No significant differences were found in the Photosystem I (PS I) and Photosystem II (PS II) contents per leaf area of the mutant compared to the wildtype parent. The decreases in the PS I and PS II antennae sizes in the mutant were not accompanied by any major changes in quantum efficiencies of PS I and PS II in leaves at non-saturating light levels for CO2 assimilation. Although the chlorophyll deficiency resulted in an 11% decrease in light absorption by mutant leaves, their maximum quantum yield and light saturated rate of CO2 assimilation were similar to those of wildtype leaves. Consequently, the large and different decreases in the antennae of PS II and PS I in the mutant are not associated with any loss of light use efficiency in photosynthesis.Abbreviations LHC I, LHC II
light harvesting chlorophyll a/b protein complexes associated with PS I and PS II
- A820
light-induced absorbance change at 820 nm
- øPS I, øPS II
relative quantum efficiencies of PS I and PS II photochemistry 相似文献
10.
A Highly Active Oxygen-Evolving Photosystem II Preparation from the Cyanobacterium Anacystis nidulans 总被引:3,自引:0,他引:3
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A highly active O2-evolving Photosystem (PS)-II fraction has been isolated from the cyanobacterium, Anacystis nidulans R2, using an isolation buffer containing high concentrations of sucrose and salts and subsequent solubilization of the thylakoid membranes with the detergent Triton X-100. The isolated fraction had very high PSII activity (2500 micromoles O2 per milligram chlorophyll per hour) and was largely depleted of PSI activity. Fluorescence emission spectra (77 K) and polypeptide analysis indicated that this preparation is highly enriched in PSII, but almost completely devoid of Cyt b6-f and PSI complexes. 相似文献
11.
The major light-harvesting chlorophyll a/b-protein (LHCP) of higher plant chloroplasts is a nuclearencoded, integral thylakoid membrane protein that binds photosynthetic pigments and occurs in situ in an oligomeric form. We have previously examined structural and functional domains of the mature apoprotein by use of mutant LHCPs and in vitro assays for uptake and insertion. Results presented here demonstrate the effects of several mutations in the amino terminal domain of the mature apoprotein. Deletion of amino acid residues 12–58 greatly affected import into chloroplasts, while deletion or alteration of the hydrophobic region E65VIHARWAM73 led to rapid degradation of the mutant LHCP. We suggest that this amino-proximal region is essential for the stability of the LHCP and its ability to integrate into the thylakoid membranes. A structural/functional relationship of this region to a previously examined hydrophobic carboxy-proximal domain [Kohorn and Tobin (1989), The Plant Cell 1, 159–166] is proposed.Abbreviations BSA
bovine serum albumin faction V
- ELIPs
early light-inducible proteins
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- LHCP
light-harvesting chlorophyll a/b-protein
- LHC IIb
light-harvesting complex associated with Photosystem II
- pLHCP
precursor to LHCP
- Rubisco
ribulose 1,5-biphosphate carboxylase-oxygenase
- SDS-PAGE
sodium dodecyl sulfate-poly-acrylamide gel electrophoresis 相似文献
12.
Reconstitution of plastoquinone in the D1/D2/cytochrome b-559 photosystem II reaction centre complex
Reconstitution of plastoquinone in the photosystem II D1/D2/cytochrome b-559 reaction centre complex, in the presence of the detergent Triton X-100, is reported. Illumination of the reconstituted system results in the reduction of cytochrome b-559, the process being partly herbicide-sensitive. In addition, the reconstitution of plastoquinone results in the ability of the isolated reaction centre to catalyse the photoreduction of 2,6-dichlorophenolindophenol in the presence of the exogenous electron donor diphenylcarbazide. 相似文献
13.
Nitrogen deficiency affects both photosystems and the antennae pigment systems in the photosynthetic apparatus of the marine alga, Cryptomonas maculata. Under increasing energy fluence rates, O2 evolution in nitrogen-deficient (-N) cell suspensions never reached a positive value; in control cultures (+N), O2 evolution increased and was saturated at about 6.4 W·m-2 with about 100 mol O2·mg chlorophyll-1·h-1. During fluorescence-induction experiments at room temperature, Fo and Fmax were significantly increased in-N cells whereas the Fvar/Fmax ratio decreased from 0.6 to 0.1. These observations can be correlated with a significantly decreased population of 12.5-nm-size particles in the exoplasmic-fracture (EF) faces of freeze-cleaved thylakoid membranes in-N cells (Rhiel et al., 1985, Protoplasma 129, 62–73). The EF particles are suggested to represent photosystem II associated with chlorophyll a/c-protein complexes (LHCP). The banding pattern of isolated and Triton X-100-solubilized thylakoid membranes of both +N and-N cells in sucrose gradients showed that the LHCP is still present in-N cells. The same applies to sodium dodecyl sulfate-polyacrylamide gel electrophoresis of these membrane fractions. The reduced number of the 12.5-nm particles in the EF faces of-N cells may be a result of decoupling of the LHCP constituents of the photosystem-II complex rather than their degradation. This is supported by high values for the initial fluorescence Fo in fluorescence-induction experiments and, in part, is indicated by the shift of the maximal fluorescence emission from 693 nm in +N to 684 nm in-N cells. The lack of the CP1 band in the gels of sodium dodecyl sulfate-solubilized thylakoid membranes from-N cells after electrophoresis demonstrates that photosystem I is also severely affected.Abbreviations Chl
chlorophyll
- CP1
chlorophyll-protein complex of PSI
- DCMU
3-(3,4-dichlorophenyl)-1,1-dimethyl urea
- LHCP
light-harvesting chlorophyll a/c protein complex
- +N/-N
control/nitrogen-deficient cell suspension cultures
- PSI (II)
photosystem I (II)
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- Tris
2-amino-2-(hydroxymethyl)-1,3-propanediol
Dedicated to Prof. Wilhelm Nultsch on the occasion of his 60th birthday 相似文献
14.
The solubilization of four integral membrane proteins (i.e. cytochrome b-561 of the chromaffin granule membrane, cytochrome b5 of the endoplasmic reticulum and the mitochondrial b-type cytochrome(s) as well as cytochrome c oxidase) has been studied at 0 °C using the non-ionic detergents of the Triton X-series having the common hydrophobic 4(1,1,3,3-tetramethylbutyl)phenoxy (t-octyl-phenoxy) group and a variable average number (
) of polar ethylene oxide units added. Following a pre-extraction of peripheral membrane and matrix proteins with low and high salt concentration and a weak non-ionic detergent (Tween 20, average hydrophile-lipophile balance (
), the amount of heme proteins solubilized by subsequent Triton X-solutions was measured. With the detergents tested the degree of solubilization decreased in the sequence cytochrome b-561 >cytochrome b5 >mitochondrial cytochrome(s) b and parallelled the effect of the detergents on light scattering and the phospholipid to protein ratio of the three membranes. For all the b-cytochromes, the solubilizing power of the detergent increased with decreasing average length of the polar ethylene oxide chain and the hydrophile-lipophile balance as long as clouding did not occur (e.g. Triton X-114,
and
). Thus, the greatest difference in the degree of solubilization of the three cytochromes was observed with Triton X-405 (
and
). All the cytochromes were most efficiently solubilized (i.e. approx. 90%) by Triton X-100 (
and
). 相似文献
15.
Triton X-100 solubilized thylakoids, isolated from Phaseolus vulgaris chloroplasts, degrade endogenous or exogenously added LHC II. The degradation, as monitored by immunodetection of the remaining LHC II after incubation at 37°C, is activated by Mg++ and inhibited by pCMB, EDTA, PMSF and benzamidine; the activity under high light conditions parallels chlorophyll photooxidation. The thylakoid-bound proteolytic activity is under phytochrome control. Etiolated plants pretreated by a white light pulse, and kept in the dark thereafter, show enhanced proteolytic activity, which follows rhythmical oscillations. On the other hand, chloramphenicol pretreatment of etiolated plants, prior to their transfer to continuous light, reduces the proteolytic activity against LHC II. The results suggest that the degradation involves a serine type protease, which depends on SH group(s), coded by the plastid genome; the protease action on LHC II is regulated by Mg++, phytochrome, the biological clock and chlorophyll accumulation in the thylakoid. The stroma lamellar fraction, separated from French press disrupted chloroplasts, exhibits higher activity towards exogenous LHC II than the grana fraction. The stroma of intact chloroplasts exhibits also high proteolytic activity, which is drastically reduced when the lysis medium is supplemented with cations. This suggests that the protease is bound mainly on stroma lamellae and peripheral granal membranes, its association to the membranes being possibly under cation control.Abbreviations CAP
chloramphenicol
- CL
continuous light
- LHC II
light harvesting complex of Photosystem II 相似文献
16.
Low-temperature (77 K) steady-state fluorescence emission spectroscopy and dynamic light scattering were applied to the main
chlorophyll a/b protein light harvesting complex of photosystem II (LHC II) in different aggregation states to elucidate the mechanism of
fluorescence quenching within LHC II oligomers. Evidences presented that LHC II oligomers are heterogeneous and consist of
large and small particles with different fluorescence yield. At intermediate detergent concentrations the mean size of the
small particles is similar to that of trimers, while the size of large particles is comparable to that of aggregated trimers
without added detergent. It is suggested that in small particles and trimers the emitter is monomeric chlorophyll, whereas
in large aggregates there is also another emitter, which is a poorly fluorescing chlorophyll associate. A model, describing
populations of antenna chlorophyll molecules in small and large aggregates in their ground and first singlet excited states,
is considered. The model enables us to obtain the ratio of the singlet excited-state lifetimes in small and large particles,
the relative amount of chlorophyll molecules in large particles, and the amount of quenchers as a function of the degree of
aggregation. These dependencies reveal that the quenching of the chl a fluorescence upon aggregation is due to the formation of large aggregates and the increasing of the amount of chlorophyll
molecules forming these aggregates. As a consequence, the amount of quenchers, located in large aggregates, is increased,
and their singlet excited-state lifetimes steeply decrease. 相似文献
17.
Interaction of Triton X-100 with the pigment-protein complexes of photosynthetic membranes.
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The interaction of the non-ionic detergent Triton X-100 with photosynthetic membrane components of Pisum sativum (pea) is described. The detergent affected both the wavelength and the intensity of the 77K fluorescence-emission peaks of both Photosystem I and Photosystem II preparations, in addition to the effects on whole thylakoids recently described by Murphy & Woodrow [(1984) Biochem. J. 224, 989-993]. Below its critical micellar concentration, Triton X-100 had no effect on 77K fluorescence emissions even after prolonged incubations of up to 30 min. Above the critical micellar concentration of about 0.16 mg X ml-1, Triton X-100 caused a dramatic increase in the intensity of the 680 nm emission. The intensity of the 680 nm fluorescence emission continued to increase as more Triton X-100 was added, until limiting concentrations of detergent were reached. These limiting concentrations were proportional to the amount of membrane present and generally occurred at Triton X-100/chlorophyll (w/w) ratios of 100-200:1. In all cases the detergent effect was seen within 10 min, and is often considerably faster, with longer detergent treatments causing no further effects. The data are discussed in terms of a three-stage mechanism for detergent solubilization of membrane components. 相似文献
18.
The light-harvesting complex (LHC) of higher plants isolated using Triton X-100 has been studied during its transformation into a monomeric form known as CPII. The change was accomplished by gradually increasing the concentration of the detergent, sodium dodecyl sulfate (SDS). Changes in the red spectral region of the absorption, circular dichroism (CD), and linear dichroism spectra occurring during this treatment have been observed at room temperature. According to a current hypothesis the main features of the visible region absorption and CD spectra of CPII can be explained reasonably successfully in terms of an exciton coupling among its chlorophyll (Chl) b molecules. We suggest that the spectral differences between the isolated LHC and the CPII may be understood basically in terms of an exciton coupling between the Chl b core of a given CPII unit and at least one of the Chla's of either the same or the adjacent CPII. We propose that this Chl a-Chl b coupling existing in LHC disappears upon segregation into CPII, probably as a result of a detergent-related overall rotation of the strongly coupled Chl b core which changes the relative orientations of the two types of pigments and thus the nature of their coupling.Abbreviations Chl
Chlorophyll
- CD
Circular dichroism
- LD
Linear dichroism
- LHC
Light-harvesting complex
- SDS
Sodium dodecyl sulfate
- CPII
A solubilized form of LHC obtained with SDS polyacrylamide gel electrophoresis
Dedicated to Prof. L.N.M. Duysens on the occasion of his retirement 相似文献
19.
Microsomal and supernatant chitinase activities have been prepared from mycelial cultures ofMucor mucedo. Studies of their responses to changing temperature and phospholipid composition indicate that the lipid environment is important in regulating membrane-bound chitinase activity, but that supernatant chitinase activity does not have a phospholipid requirement. Membrane-bound chitinase was solubilized by different types of non-denaturing detergents. Maximum solubilization was achieved with 1 mM Zwittergent-14 or 1.2% Triton X-100 (93% and 90% solubilization, respectively). This solubilized chitinase activity could not be activated by protease treatment, i.e., was nonzymogenic, as was the supernatant chitinase. The insoluble residual chitinase activity was, however, zymogenic after treatment with 1.2% Triton X-100, but fully active after treatment with 3% Triton X-100. 相似文献
20.
Jeanette S. Brown 《Photosynthesis research》1983,4(4):375-383
The three major chlorophyll-proteins of spinach chloroplasts were solubilized with digitonin and isolated by electrophoresis with deoxycholate. The gel bands were identified from their absorption and fluorescence spectra measured at 77 K. The slowest moving band was a Photosystem I complex (CPI); the second, a Photosystem II complex (Cpa); and the third, a chlorophyll a-b, antenna complex (LHCP). When absorption spectra (630–730 nm) of the bands were added in the proportions found in the gel, the sum closely matched the absorption of the chloroplasts both before and after solubilization. Thus these spectra represent the native absorption of the major antenna chlorophyll-proteins of green plants. Each of these spectra was resolved with a computer assisted, curve-fitting program into 8 mixed Gaussian-Lorentzian shaped components. The major, Chl a components in the 3 fractions were different both in peak positions and bandwidths. This result suggests that each chlorophyll-protein has its own unique set of chlorophyll a spectral forms or components.Abbreviations Chl
chlorophyll
- CPI
Photosystem I Chl-protein
- CPa
Photosystem II Chl-protein
- LHCP
light-harvesting Chl a-b protein
- DOC
sodium deoxycholate
- SDS
sodium dodecylsulfate
CIW-DPB No. 819 相似文献