Phase Partition—A Method for Purification and Analysis of Cell Organelles and Membrane Vesicles

Albertsson, Per‐Åke; Andersson, Bertil; Larsson, Christer; Åkerlund, Hans‐Erik

doi:10.1002/9780470110485.ch2

Cited by 145 publications

(9 citation statements)

References 73 publications

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“…The pellet containing the microsomes was resuspended in 0.5 M sorbitol dissolved in 3 mM Tris‐maleate buffer (pH 7.3) to give protein concentrations of ∼5 µg µl −1 . For purification of plasma membranes, microsomes were loaded onto a polymer two‐phase system (Albertsson, 1970; 1982; Yoshida et al ., 1983) buffered with 0.5 M sorbitol dissolved in 10 mM potassium phosphate (pH 7.6). Optimal polymer concentrations were 6% for C. juncea , 5.9% for V. unguiculata , F. congesta and P. tuberosus and 5.8% for T. vogelii.…”

Section: Methodsmentioning

confidence: 99%

NopP, a phosphorylated effector of Rhizobium sp. strain NGR234, is a major determinant of nodulation of the tropical legumes Flemingia congesta and Tephrosia vogelii

Skorpil

Saad

Boukli

et al. 2005

Molecular Microbiology

136

128

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SummaryRhizobium sp. NGR234 nodulates many plants, some of which react to proteins secreted via a type three secretion system (T3SS) in a positive-( Flemingia congesta , Tephrosia vogelii ) or negative-( Crotalaria juncea , Pachyrhizus tuberosus ) manner. T3SSs are devices that Gram-negative bacteria use to inject effector proteins into the cytoplasm of eukaryotic cells. The only two rhizobial T3SS effector proteins characterized to date are NopL and NopP of NGR234. NopL can be phosphorylated by plant kinases and we show this to be true for NopP as well. Mutation of nopP leads to a dramatic reduction in nodule numbers on F. congesta and T. vogelii . Concomitant mutation of nopL and nopP further diminishes nodulation capacity to levels that, on T. vogelii , are lower than those produced by the T3SS null mutant NGR W W W W rhcN . We also show that the T3SS of NGR234 secretes at least one additional effector, which remains to be identified. In other words, NGR234 secretes a cocktail of effectors, some of which have positive effects on nodulation of certain plants while others are perceived negatively and block nodulation. NopL and NopP are two components of this mix that extend the ability of NGR234 to nodulate certain legumes.

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Section: Methodsmentioning

confidence: 99%

NopP, a phosphorylated effector of Rhizobium sp. strain NGR234, is a major determinant of nodulation of the tropical legumes Flemingia congesta and Tephrosia vogelii

Skorpil

Saad

Boukli

et al. 2005

Molecular Microbiology

136

128

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“…Grana membranes can be purified (the so-called BBY particles) that contain practically only PSII complexes (Berthold et al 1981 ; Dunahay et al 1984 ; Albertsson et al 1981 ), although it is not completely understood how PSII is organized in these membranes. It had been suggested that C2S2 represents the supercomplex in high light, while C2S2M2 is the result of low-light growth (Daum et al 2010 ).…”

Section: Energy Transfer and Charge Separation In Psii Membranesmentioning

confidence: 99%

Light harvesting in photosystem II

2013

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Water oxidation in photosynthesis takes place in photosystem II (PSII). This photosystem is built around a reaction center (RC) where sunlight-induced charge separation occurs. This RC consists of various polypeptides that bind only a few chromophores or pigments, next to several other cofactors. It can handle far more photons than the ones absorbed by its own pigments and therefore, additional excitations are provided by the surrounding light-harvesting complexes or antennae. The RC is located in the PSII core that also contains the inner light-harvesting complexes CP43 and CP47, harboring 13 and 16 chlorophyll pigments, respectively. The core is surrounded by outer light-harvesting complexes (Lhcs), together forming the so-called supercomplexes, at least in plants. These PSII supercomplexes are complemented by some “extra” Lhcs, but their exact location in the thylakoid membrane is unknown. The whole system consists of many subunits and appears to be modular, i.e., both its composition and organization depend on environmental conditions, especially on the quality and intensity of the light. In this review, we will provide a short overview of the relation between the structure and organization of pigment-protein complexes in PSII, ranging from individual complexes to entire membranes and experimental and theoretical results on excitation energy transfer and charge separation. It will become clear that time-resolved fluorescence data can provide invaluable information about the organization and functioning of thylakoid membranes. At the end, an overview will be given of unanswered questions that should be addressed in the near future.

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“…Grana membranes and subfractions of grana membranes can be purified and they were shown to contain practically only PSII complexes [151][152][153]. However, it is not completely understood how the complexes are organized in the membrane.…”

Section: Psii Organization In the Grana Membranesmentioning

confidence: 99%

Light-harvesting and structural organization of Photosystem II: From individual complexes to thylakoid membrane

Croce

Amerongen

2011

Journal of Photochemistry and Photobiology B: Biology

162

114

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a b s t r a c tPhotosystem II (PSII) is responsible for the water oxidation in photosynthesis and it consists of many proteins and pigment-protein complexes in a variable composition, depending on environmental conditions. Sunlight-induced charge separation lies at the basis of the photochemical reactions and it occurs in the reaction center (RC). The RC is located in the PSII core which also contains light-harvesting complexes CP43 and CP47. The PSII core of plants is surrounded by external light-harvesting complexes (lhcs) forming supercomplexes, which together with additional external lhcs, are located in the thylakoid membrane where they perform their functions.In this paper we provide an overview of the available information on the structure and organization of pigment-protein complexes in PSII and relate this to experimental and theoretical results on excitation energy transfer (EET) and charge separation (CS). This is done for different subcomplexes, supercomplexes, PSII membranes and thylakoid membranes. Differences in experimental and theoretical results are discussed and the question is addressed how results and models for individual complexes relate to the results on larger systems. It is shown that it is still very difficult to combine all available results into one comprehensive picture.

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Phase Partition—A Method for Purification and Analysis of Cell Organelles and Membrane Vesicles

Cited by 145 publications

References 73 publications

NopP, a phosphorylated effector of Rhizobium sp. strain NGR234, is a major determinant of nodulation of the tropical legumes Flemingia congesta and Tephrosia vogelii

NopP, a phosphorylated effector of Rhizobium sp. strain NGR234, is a major determinant of nodulation of the tropical legumes Flemingia congesta and Tephrosia vogelii

Light harvesting in photosystem II

Light-harvesting and structural organization of Photosystem II: From individual complexes to thylakoid membrane

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