Thermo-optically Induced Reorganizations in the Main Light Harvesting Antenna of Plants. II. Indications for the Role of LHCII-only Macrodomains in Thylakoids

Holm, Jesper; Várkonyi, Zsuzsanna; Kovács, László; Posselt, Dorthe; Garab, Győző

doi:10.1007/s11120-005-5302-x

Cited by 28 publications

(24 citation statements)

References 40 publications

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“…It is unclear and cannot be discriminated based on the presently available data, if this partial disassociation of LHCII from PSII occurs only at the level of supercomplexes, or involves or rather preferentially occurs in the LHCII-only domains (Dekker and Boekema 2005). Based on transient CD spectra, it has been argued earlier (Holm et al 2005) that LHCII-only domains are more readily amenable for reorganizations. Their direct involvement in regular processes is more plausible than the involvement of LHCII-PSII supercomplexes.…”

Section: Resultsmentioning

confidence: 99%

Effect of phosphorylation on the thermal and light stability of the thylakoid membranes

et al. 2008

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Higher plant thylakoid membranes contain a protein kinase that phosphorylates certain threonine residues of light-harvesting complex II (LHCII), the main light-harvesting antenna complexes of photosystem II (PSII) and some other phosphoproteins (Allen, Biochim Biophys Acta 1098: 275, 1992). While it has been established that phosphorylation induces a conformational change of LHCII and also brings about changes in the lateral organization of the thylakoid membrane, it is not clear how phosphorylation affects the dynamic architecture of the thylakoid membranes. In order to contribute to the elucidation of this complex question, we have investigated the effect of duroquinol-induced phosphorylation on the membrane ultrastructure and the thermal and light stability of the chiral macrodomains and of the trimeric organization of LHCII. As shown by small angle neutron scattering on thylakoid membranes, duroquinol treatment induced a moderate (*10%) increase in the repeat distance of stroma membranes, and phosphorylation caused an additional loss of the scattering intensity, which is probably associated with the partial unstacking of the granum membranes. Circular dichroism (CD) measurements also revealed only minor changes in the chiral macro-organization of the complexes and in the oligomerization state of LHCII. However, temperature dependences of characteristic CD bands showed that phosphorylation significantly decreased the thermal stability of the chiral macrodomains in phosphorylated compared to the non-phosphorylated samples (in leaves and isolated thylakoid membranes, from 48.3°C to 42.6°C and from 47.5°C to 44.3°C, respectively). As shown by non-denaturing PAGE of thylakoid membranes and CD spectroscopy on EDTA washed membranes, phosphorylation decreased by about 5°C, the trimer-tomonomer transition temperature of LHCII. It also enhanced the light-induced disassembly of the chiral macrodomains and the monomerization of the LHCII trimers at 25°C. These data strongly suggest that phosphorylation of the membranes considerably facilitates the heat-and lightinducible reorganizations in the thylakoid membranes and thus enhances the structural flexibility of the membrane architecture.

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Section: Resultsmentioning

confidence: 99%

Effect of phosphorylation on the thermal and light stability of the thylakoid membranes

et al. 2008

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“…An important role of light-induced LHCII reorganization in photoprotection against light-induced damage has emerged from several studies, both in vivo and in vitro (Barzda et al, 1996;Dobrikova et al, 2003;Cseh et al, 2005;Holm et al, 2005;Gruszecki et al, 2009b;Johnson et al, 2011). Most of these data suggest that the primary site of light-induced reorganizations is on the outer loop segments of LHCII, affecting the phosphorylation (Zer et al, 1999), the cation binding sites (Cseh et al, 2000;Garab and Mustardy, 2000), and the ability of stacking and lateral reorganizations (Dobrikova et al, 2003;Gruszecki et al, 2009b).…”

Section: Discussionmentioning

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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“…Black and white horizontal bars indicate dark and light periods, respectively; the schematic illustration shows that upon illumination of the sample with excess light, the long-range order of the complexes is perturbed (panel a ). Very similar kinetics are displayed by all main psi-type CD bands, indicating an overall reorganization of the chiral macrodomains in the grana (Garab et al 1988 ;Holm et al 2005 ). Panel b is reproduced from Garab ( 2014 ).…”

Section: A Involvement Of Structural Changes In Light-adaptation Mechmentioning

confidence: 67%

“…A large fraction of LHCII trimers are only loosely associated with the PS II supercomplex or are found in LHCII-only domains (Boekema et al 2000 ), and these readily detach from PS II as suggested by Holm et al ( 2005 ). Light-induced detachment of the phycobilisome antenna has also been observed in cyanobacteria under conditions that trigger NPQ (Stoitchkova et al 2007 ).…”

Section: Functional Domain Sizes and The Effective Radii Of Quenchersmentioning

confidence: 99%

Thermo-optically Induced Reorganizations in the Main Light Harvesting Antenna of Plants. II. Indications for the Role of LHCII-only Macrodomains in Thylakoids

Cited by 28 publications

References 40 publications

Effect of phosphorylation on the thermal and light stability of the thylakoid membranes

Effect of phosphorylation on the thermal and light stability of the thylakoid membranes

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

Structural Changes and Non-Photochemical Quenching of Chlorophyll a Fluorescence in Oxygenic Photosynthetic Organisms

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