Chromatic Adaptation of Photosynthetic Membranes

Scheuring, Simon; Sturgis, James N.

doi:10.1126/science.1110879

Cited by 266 publications

(323 citation statements)

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“…Future applications of polymer-based LH nanocomposites could also allow the non-covalent incorporation of biological electron carriers, 34 or carbon nanomaterials such as fullerenes 35,36 or carbon nanotubes 37 , allowing electron-active assemblies and new functional devices. Photosynthetic membranes are highly responsive, often changing the composition and organization of LH pigment-protein components in response external stimuli, such as light intensity [38][39][40] , oxygen tension, 40 and genetic mutation. 41,42 Mimicking and expanding such responsive behavior is also highly desirable in generation of artificial light-harvesting systems.…”

Section: Figure 4 Energy Transfer and Chromophore Mobility In Suppormentioning

confidence: 99%

Diblock Copolymer Micelles and Supported Films with Noncovalently Incorporated Chromophores: A Modular Platform for Efficient Energy Transfer

et al. 2015

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We report generation of modular, artificial light-harvesting assemblies where an amphiphilic diblock copolymer, poly(ethylene oxide)-block-poly(butadiene), serves as the framework for noncovalent organization of BODIPY-based energy donor and bacteriochlorin-based energy acceptor chromophores. The assemblies are adaptive and form well-defined micelles in aqueous solution and high-quality monolayer and bilayer films on solid supports, with the latter showing greater than 90% energy transfer efficiency. This study lays the groundwork for further development of modular, polymer-based materials for light harvesting and other photonic applications

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Section: Figure 4 Energy Transfer and Chromophore Mobility In Suppormentioning

confidence: 99%

Diblock Copolymer Micelles and Supported Films with Noncovalently Incorporated Chromophores: A Modular Platform for Efficient Energy Transfer

et al. 2015

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“…Recent progress in time-lapse AFM showed, in real time, the change in height of the pore protrusion from the membrane of cytolysin within its formation [79]. Scheuring and Sturgis [80] have even managed to image photosynthetic membranes with a spatial resolution of 1nm. They have analysed and modelled its composition and architectural modifications in response to light.…”

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What do diffusion measurements tell us about membrane compartmentalisation? Emergence of the role of interprotein interactions

2008

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The techniques of diffusion analysis based on optical microscopy approaches have revealed a great diversity of the dynamic organisation of cell membranes. For a long period, two frameworks have dominated the way of representing the membrane structure: the membrane skeleton fences and the lipid raft models. Progresses in the methods of data analysis have shed light on the features and consequently the possible origin of membrane domains: Inter-protein interactions play a role in confinement. Innovative developments pushing forward the spatiotemporal resolution limits are currently emerging, which are likely to provide in the future a detailed understanding of the intimate functional dynamic organisation of the cell membrane. Keywords Membrane domain . Diffusion . Protein interaction OverviewThe main function of membranes is to generate close compartments: The cell itself (by the plasma membrane) and also the nucleus (by nuclear envelope), the Golgi apparatus, the endoplasmic reticulum, various organelles or the vesicles which are involved in transport processes. Membranes delimit these structures and allow them to have a different composition from the rest of the cell by restricting the diffusion of ions and macromolecules. The specific transport of molecules or information across the membrane is devoted to membrane proteins. Membranes are essentially composed of lipid and proteins, each of them representing about 50% in weight. Lipids are amphiphilic molecules that spontaneously form a bilayer in water. Among the variety of lipids, cholesterol has a specific place since it is particularly abundant in eukaryotic cells. Cholesterol can modify the lipid molecular order [1] and is presumed to participate in lipid micro-phase separation (rafts) [2][3][4][5].Since the structure of biological membranes is maintained by non-covalent bonds, they have first been considered as a fluid lipid bilayer in which embedded proteins are free to diffuse [6]. After the advent of this fluid mosaic model postulating a random distribution of membrane molecules [6], experimental evidence showed that the proteins and lipids are distributed heterogeneously in the membrane. For example, incomplete recoveries were systematically observed in fluorescence recovery after photobleaching (FRAP; see "Appendix 1") experiments. The first indication of the presence of micrometer-sized domains was obtained by FRAP. Yechiel and Edidin found a decrease of the mobile fraction with increasing radius of the bleaching spot ([7, 8] and see "Appendix 1").The huge diversity of lipids and proteins implies that a very large number of combinatorial interactions can occur between them [9]. Since all lipids and proteins do not J Chem Biol (2008) [14,15]. Interactions of membrane proteins with the cytoskeleton or with the glycocalyx can also affect the membrane organisation and are likely to play a confining role [16]. A significant challenge of cell biology is to characterise and to understand not only the origin but also the role of these micrometric ...

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“…Extra LH2 are synthesized to increase the effective reaction center absorption cross section (18,19). This modification is associated with the formation of large para-crystalline domains of LH2 in the photosynthetic membranes (20). Such domains have now been observed in several different bacteria including Ph.…”

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confidence: 99%

Antenna mixing in photosynthetic membranes from Phaeospirillum molischianum

Mascle-Allemand¹,

Duquesne²,

Lebrun

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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We have investigated the adaptation of the light-harvesting system of the photosynthetic bacterium Phaeospirillum molischianum (DSM120) to very low light conditions. This strain is able to respond to changing light conditions by differentially modulating the expression of a family of puc operons that encode for peripheral light-harvesting complex (LH2) polypeptides. This modulation can result in a complete shift between the production of LH2 complexes absorbing maximally near 850 nm to those absorbing near 820 nm. In contradiction to prevailing wisdom, analysis of the LH2 rings found in the photosynthetic membranes during light adaptation are shown to have intermediate spectral and electrostatic properties. By chemical cross-linking and mass-spectrometry we show that individual LH2 rings and subunits can contain a mixture of polypeptides derived from the different operons. These observations show that polypeptide synthesis and insertion into the membrane are not strongly coupled to LH2 assembly. We show that the light-harvesting complexes resulting from this mixing could be important in maintaining photosynthetic efficiency during adaptation.chromatic adaptation | membrane protein | photosynthetic bacteria | Rhodospirillum molischianum P hotosynthetic bacteria are able to efficiently convert incident light into chemical potential energy via a light-driven cyclic electron transfer pathway (1). This process depends on the efficient absorption of incident light energy and the transfer of this energy to the reaction center. Measurements of the quantum efficiency of the light-harvesting apparatus indicate that very little energy is lost during the migration of the exciton from the point of initial absorption to the reaction center (1). The light-harvesting system of many bacteria contains two different pigment-protein complexes. The core complex contains one or two reaction centers in close association with a light-harvesting system (LH1) and a smaller peripheral complex (LH2) that transfers the absorbed excitation energy to the core complex. Both types of light-harvesting complex, LH1 and LH2, are constructed from oligomers of a similar basic subunit containing 2 polypeptides (α and β) with associated bacteriochlorophyll and carotenoid pigments. Their structures are known from x-ray crystallography (2-4), electron crystallography (5), and more recently from atomic force microscopy (6-11).The LH2 complexes are circular oligomers of typically 9 αβ subunits (3), in which 18 long wavelength-absorbing bacteriochlorophyll molecules are sandwiched between the inner ring of α-polypeptides and an outer-ring of β-polypeptides. A second series of 9 bacteriochlorohpyll molecules, closer to the cytoplasmic membrane surface, occupies gaps between the β-polypeptides. This general architecture is slightly variable, with in particular the number of monomeric units forming the circular architecture depending on the species and environmental conditions (2,7,12,13). In the species studied in this work, Phaeospirillum (Ph.) molischianum...

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Chromatic Adaptation of Photosynthetic Membranes

Cited by 266 publications

References 28 publications

Diblock Copolymer Micelles and Supported Films with Noncovalently Incorporated Chromophores: A Modular Platform for Efficient Energy Transfer

Diblock Copolymer Micelles and Supported Films with Noncovalently Incorporated Chromophores: A Modular Platform for Efficient Energy Transfer

What do diffusion measurements tell us about membrane compartmentalisation? Emergence of the role of interprotein interactions

Antenna mixing in photosynthetic membranes from Phaeospirillum molischianum

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