A Post-translational Modification of the Photosystem II Subunit CP29 Protects Maize from Cold Stress

Bergantino, Elisabetta; Dainese, Paola; Cerović, Zoran G.; Sechi, Salvatore; Bassi, Roberto

doi:10.1074/jbc.270.15.8474

Cited by 115 publications

(119 citation statements)

References 46 publications

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“…IEF allows for detection of small changes in the pI of a protein, which often result from conformational changes, such as ligand binding in both soluble (Ek et al, 1980) and membrane proteins (Ben Or and Chrambach, 1983), or posttranslational modifications, such as phosphorylation in the case of CP29 (Bergantino et al, 1995). The analysis of monomeric LHC proteins in npq2 clearly shows that CP26 migrates at two different pH values, whereas in dark-adapted wild type and npq1 only the more acidic band could be detected ( Figure 5A).…”

Section: What Is the Molecular Basis Of This Quenching Effect?mentioning

confidence: 99%

“…Changes in the pI of a membrane protein may reveal conformational (Ben Or and Chrambach, 1983) and/or posttranslational modifications, such as phosphorylation (Bergantino et al, 1995), which change the exposed charges of proteins. To verify if zeaxanthin binding was the only cause for the change in pI, recombinant holoproteins were produced by overexpressing At-Lhcb5 cDNA in Escherichia coli and reconstituting in vitro the apoprotein with chlorophyll a and chlorophyll b plus either a mixture of Lute þ Viola þ Neo or Lute þ Zea.…”

Section: Recombinant Cp26 Proteins With Distinct Xanthophyll Compositmentioning

confidence: 99%

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A Mechanism of Nonphotochemical Energy Dissipation, Independent from PsbS, Revealed by a Conformational Change in the Antenna Protein CP26

2005

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The regulation of light harvesting in higher plant photosynthesis, defined as stress-dependent modulation of the ratio of energy transfer to the reaction centers versus heat dissipation, was studied by means of carotenoid biosynthesis mutants and recombinant light harvesting complexes (LHCs) with modified chromophore binding. The npq2 mutant of Arabidopsis thaliana, blocked in the biosynthesis of violaxanthin and thus accumulating zeaxanthin, was shown to have a lower fluorescence yield of chlorophyll in vivo and, correspondingly, a higher level of energy dissipation, with respect to the wildtype strain and npq1 mutant, the latter of which is incapable of zeaxanthin accumulation. Experiments on purified thylakoid membranes from all three mutants showed that the major source of the difference between the npq2 and wild-type preparations was a change in pigment to protein interactions, which can explain the lower chlorophyll fluorescence yield in the npq2 samples. Analysis of the xanthophyll binding LHC proteins showed that the Lhcb5 photosystem II subunit (also called CP26) undergoes a change in its pI upon binding of zeaxanthin. The same effect was observed in wild-type CP26 upon treatment that leads to the accumulation of zeaxanthin in the membrane and was interpreted as the consequence of a conformational change. This hypothesis was confirmed by the analysis of two recombinant proteins obtained by overexpression of the Lhcb5 apoprotein in Escherichia coli and reconstitution in vitro with either violaxanthin or zeaxanthin. The V and Z containing pigment-protein complexes obtained by this procedure showed different pIs and high and low fluorescence yields, respectively. These results confirm that LHC proteins exist in multiple conformations, an idea suggested by previous spectroscopic measurements ( Moya et al., 2001), and imply that the switch between the different LHC protein conformations is activated by the binding of zeaxanthin to the allosteric site L2. The results suggest that the quenching process induced by the accumulation of zeaxanthin contributes to qI, a component of NPQ whose origin was previously poorly understood.

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Section: What Is the Molecular Basis Of This Quenching Effect?mentioning

confidence: 99%

Section: Recombinant Cp26 Proteins With Distinct Xanthophyll Compositmentioning

confidence: 99%

A Mechanism of Nonphotochemical Energy Dissipation, Independent from PsbS, Revealed by a Conformational Change in the Antenna Protein CP26

2005

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“…Because the CP26, CP24, and CP29 complexes bind the majority of the xanthophyll cycle carotenoids, it has been suggested that they constitute the primary site of the NPQ mechanism and, as such, play an important role in regulating energy flow from the bulk LHC IIb to the PS II reaction center. Support for this assignment has emerged from the identification of protonation sites in CP26 and CP29 (27)(28)(29), thought to correspond to the low luminal pH requirement for nonphotochemical quenching, and from the fact that CP29 is reversibly phosphorylated under stress conditions (30), suggesting an involvement in stress resistance.…”

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confidence: 99%

Photochemical Behavior of Xanthophylls in the Recombinant Photosystem II Antenna Complex, CP26

et al. 2001

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The steady state absorption and fluorescence spectroscopic properties of the xanthophylls, violaxanthin, zeaxanthin, and lutein, and the efficiencies of singlet energy transfer from the individual xanthophylls to chlorophyll have been investigated in recombinant CP26 protein overexpressed in Escherichia coli and then refolded in vitro with purified pigments. Also, the effect of the different xanthophylls on the extents of static and dynamic quenching of chlorophyll fluorescence has been investigated. Absorption, fluorescence, and fluorescence excitation demonstrate that the efficiency of light harvesting from the xanthophylls to chlorophyll a is relatively high and insensitive to the particular xanthophyll that is present. A small effect of the different xanthophylls is observed on the extent of quenching of Chl fluorescence. The data provide the precise wavelengths of the absorption and fluorescence features of the bound pigments in the highly congested spectral profiles from these light-harvesting complexes. This information is important in assessing the mechanisms by which higher plants dissipate excess energy in light-harvesting proteins.Light-harvesting pigment-protein complexes in higher plants and algae possess a means of thermally dissipating photon energy absorbed, but not used, in photosynthesis. The process is known as nonphotochemical quenching (NPQ) 1 and offers a short-term protective response to changes in incident light energy irradiance (1-3). Dissipation of excess energy in light-harvesting proteins from photosynthetic systems can be measured quantitatively by observing the extent to which fluorescence from chlorophyll (Chl) a bound in the complexes is affected by different chemical and physical conditions (4-11). NPQ is known to be associated with acidification of the thylakoid lumen and correlated with the enzymatic interconversion of violaxanthin and zeaxanthin in the xanthophyll cycle (12, 13). What is not clear, however, is precisely how the interconversion of the pigments in the xanthophyll cycle is associated with thermal dissipation. Two basic hypotheses for the involvement of the xanthophylls have been presented in the literature: direct quenching and indirect quenching.The direct quenching model invokes specific energy states of xanthophyll molecules in the process of quenching (1,(13)(14)(15). Optical spectroscopic investigations of carotenoids and xanthophylls have shown that the energies of the lowest excited (S 1 ) states of some of these molecules may be sufficiently low to quench Chl excited states, thus providing a means of regulating the flow of energy in the antenna (16)(17)(18)(19). Determinations of the S 1 excited state energies of violaxanthin and zeaxanthin suggest that although the direct route of quenching of excited states of Chl a by these molecules is energetically feasible, the energy difference between the S 1 states of zeaxanthin and violaxanthin is not large enough to account for the magnitude of differential quenching associated with these pigments an...

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“…Other protein components that undergo reversible phosphorylation are D1, D2, CP43, and CP29 (Bennett, 1984;Bergantino et al, 1995). The LHCII complex is phosphorylated on the N-terminal Thr by STN7 kinase (Depège et al, 2003), which causes the complex to detach from photosystem II (PSII) in grana regions and its longrange diffusion toward the stroma lamellae.…”

Section: Introductionmentioning

confidence: 99%

Molecular Architecture of Plant Thylakoids under Physiological and Light Stress Conditions: A Study of Lipid-Light-Harvesting Complex II Model Membranes

et al. 2013

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In this study, we analyzed multibilayer lipid-protein membranes composed of the photosynthetic light-harvesting complex II (LHCII; isolated from spinach [Spinacia oleracea]) and the plant lipids monogalcatosyldiacylglycerol and digalactosyldiacylglycerol. Two types of pigment-protein complexes were analyzed: those isolated from dark-adapted leaves (LHCII) and those from leaves preilluminated with high-intensity light (LHCII-HL). The LHCII-HL complexes were found to be partially phosphorylated and contained zeaxanthin. The results of the x-ray diffraction, infrared imaging microscopy, confocal laser scanning microscopy, and transmission electron microscopy revealed that lipid-LHCII membranes assemble into planar multibilayers, in contrast with the lipid-LHCII-HL membranes, which form less ordered structures. In both systems, the protein formed supramolecular structures. In the case of LHCII-HL, these structures spanned the multibilayer membranes and were perpendicular to the membrane plane, whereas in LHCII, the structures were lamellar and within the plane of the membranes. Lamellar aggregates of LHCII-HL have been shown, by fluorescence lifetime imaging microscopy, to be particularly active in excitation energy quenching. Both types of structures were stabilized by intermolecular hydrogen bonds. We conclude that the formation of trans-layer, rivet-like structures of LHCII is an important determinant underlying the spontaneous formation and stabilization of the thylakoid grana structures, since the lamellar aggregates are well suited to dissipate excess energy upon overexcitation.

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A Post-translational Modification of the Photosystem II Subunit CP29 Protects Maize from Cold Stress

Cited by 115 publications

References 46 publications

A Mechanism of Nonphotochemical Energy Dissipation, Independent from PsbS, Revealed by a Conformational Change in the Antenna Protein CP26

A Mechanism of Nonphotochemical Energy Dissipation, Independent from PsbS, Revealed by a Conformational Change in the Antenna Protein CP26

Photochemical Behavior of Xanthophylls in the Recombinant Photosystem II Antenna Complex, CP26

Molecular Architecture of Plant Thylakoids under Physiological and Light Stress Conditions: A Study of Lipid-Light-Harvesting Complex II Model Membranes

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