Effect of light-harvesting complex II on ion transport across model lipid membranes

Wardak, Aneta; Brodowski, Ryszard; Krupa, Zbigniew; Gruszecki, Wiesław I.

doi:10.1016/s1011-1344(00)00050-6

Cited by 17 publications

(7 citation statements)

References 28 publications

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“…This pocket is right beneath (about 7 Å ) the cavity (c). Flexible side chains (a) in the lumenexposed surface may tune the size of the entrance Photosynth Res (2011) 107:169-175 173 (Wardak et al 2000;Iwaszko et al 2004). This pocket (Fig.…”

Section: Discussionmentioning

confidence: 99%

Polyamines stimulate non-photochemical quenching of chlorophyll a fluorescence in Scenedesmus obliquus

2011

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Polyamines (PAs) are small metabolites that are produced and oxidized in chloroplasts with an obscure mode of action. Recently, we showed that qE is stimulated by PAs in higher plants (Nicotiana tabacum) and in genetically modified plants with elevated thylakoid-associated PAs (Ioannidis and Kotzabasis Biochim Biophys Acta 1767:1371-1382, 2007; Ioannidis et al. Biochim Biophys Acta 1787:1215-1222, 2009). Here, we investigated further their quenching properties both in vivo in green algae and in vitro is isolated LHCII. In vivo spermine up-regulates NPQ in Scenedesums obliquus about 30%. In vitro putrescine--the obligatory metabolic precursor of PAs--has a marginal quenching effect, while spermidine and spermine exhibit strong quenching abilities in isolated LHCII up to 40%. Based on available 3D models of LHCII we report a special cavity of about 600 Å(3) and a near-by larger pocket in the trimeric LHCII that could be of importance for the stimulation of qE by amines.

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Section: Discussionmentioning

confidence: 99%

Polyamines stimulate non-photochemical quenching of chlorophyll a fluorescence in Scenedesmus obliquus

2011

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“…Due to the presence of two types of photosystems within the membrane as well as two types of excitation quenchers (RCs and NPQ-traps), the spectroscopic signatures of various parallel processes occurring in the thylakoid membrane are not easily resolved [5][6][7][8][9] , which severely complicates the detailed direct investigation of the molecular mechanisms involved. Instead, different photosynthetic units or just pigment-protein complexes are usually extracted from the thylakoid membrane and then are studied separately either in the detergent-solubilized form utilizing conventional bulk spectroscopy methods [10][11][12][13][14][15][16][17] or being immobilized on some surface while applying the single-molecule microscopy techniques [18][19][20][21][22] . Such treatment in the non-native environment allows much more straightforward analysis of the collected data but does not ensure that all the observations directly correspond to the in vivo processes and not to the side effect of the detergent micelle environment.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence Microscopy of Single Liposomes with Incorporated Pigment–Proteins

et al. 2018

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Reconstitution of transmembrane proteins into liposomes is a widely used method to study their behavior under conditions closely resembling the natural ones. However, this approach does not allow precise control of the liposome size, reconstitution efficiency and the actual protein-to-lipid ratio in the formed proteoliposomes, which might be critical for some applications and/or interpretation of data acquired during the spectroscopic measurements. Here we present a novel strategy employing methods of proteoliposome preparation, fluorescent labelling, purification, and surface immobilization that allow us to quantify these properties using fluorescence microscopy at the single-liposome level and for the first time apply it to study photosynthetic pigment-protein complexes LHCII. We show that LHCII proteoliposome samples, even after purification with a density gradient, always contain a fraction of non-reconstituted protein and are extremely heterogeneous in both protein density and liposome sizes. This strategy enables quantitative analysis of the reconstitution efficiency of different protocols and precise fluorescence spectroscopic study of various transmembrane proteins in a controlled native-like environment.

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“…Detergent-isolated complexes can be incorporated back into a lipid environment to investigate this dependence on the environment. A variety of ensemble studies have been performed on LHC complexes incorporated into liposomes, a spherical vesicle consisting of a lipid bilayer shell around an aqueous core [55][56][57][58][59]. Those experiments also contain the effect of protein-protein interaction of multiple complexes within a single liposome which makes it difficult to extract purely the influence of the lipid environment [60].…”

Section: Lipid Environmentmentioning

confidence: 99%

From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective

et al. 2017

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Abstract:The conversion of solar radiation to chemical energy in plants and green algae takes place in the thylakoid membrane. This amphiphilic environment hosts a complex arrangement of light-harvesting pigment-protein complexes that absorb light and transfer the excitation energy to photochemically active reaction centers. This efficient light-harvesting capacity is moreover tightly regulated by a photoprotective mechanism called nonphotochemical quenching to avoid the stress-induced destruction of the catalytic reaction center. In this review we provide an overview of single-molecule fluorescence measurements on plant light-harvesting complexes (LHCs) of varying sizes with the aim of bridging the gap between the smallest isolated complexes, which have been well-characterized, and the native photosystem. The smallest complexes contain only a small number (10-20) of interacting chlorophylls, while the native photosystem contains dozens of protein subunits and many hundreds of connected pigments. We discuss the functional significance of conformational dynamics, the lipid environment, and the structural arrangement of this fascinating nanomachinery. The described experimental results can be utilized to build mathematical-physical models in a bottom-up approach, which can then be tested on larger in vivo systems. The results also clearly showcase the general property of biological systems to utilize the same system properties for different purposes. In this case it is the regulated conformational flexibility that allows LHCs to switch between efficient light-harvesting and a photoprotective function.

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Effect of light-harvesting complex II on ion transport across model lipid membranes

Cited by 17 publications

References 28 publications

Polyamines stimulate non-photochemical quenching of chlorophyll a fluorescence in Scenedesmus obliquus

Polyamines stimulate non-photochemical quenching of chlorophyll a fluorescence in Scenedesmus obliquus

Fluorescence Microscopy of Single Liposomes with Incorporated Pigment–Proteins

From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective

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