LINEAR DICHROISM(250–700 nm) OF CHLOROPHYLL a AND PHEOPHYTIN a ORIENTED IN A LAMELLAR PHASE OF GLYCERYLMONOOCTANOATE/H2O. CHARACTERIZATION OF ELECTRONIC TRANSITIONS

Fragata, M.; Nordén, Bengt; Kurucsev, Tomas

doi:10.1111/j.1751-1097.1988.tb02703.x

Cited by 97 publications

(132 citation statements)

References 37 publications

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“…No common values of FN were obtained upon varying in steps of 10°the value of the R angle (between 60°and 100°for Chl a and between 51°and 91°for Chl b). Again, no common values of FN could be found upon using in the computation the alternative angles considered by Fragata et al (38) for the Q y transition (110°and 119°). The final value of 204 for FN has been estimated to give the minimal rootmean-square deviation within the group of selected results.…”

Section: Cp29 Structuralmentioning

confidence: 98%

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Orientation of Chlorophyll Transition Moments in the Higher-Plant Light-Harvesting Complex CP29

et al. 1999

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The Q y transition dipole moment vectors of all eight chlorophylls in the higher-plant antenna protein CP29 were calculated by an original method on the basis of linear dichroism and absorption spectroscopy. The contribution of individual chromophores was determined from difference spectra between wild type and mutant proteins in which a single chlorophyll has been removed by mutating pigmentbinding residues. Recombinant proteins were constructed by overexpressing the apoprotein in bacteria and refolding of the pigment-protein complex in vitro [Bassi, R., Croce, R., Cugini, D., and Sandonà, D. (1999) Proc. Natl. Acad. Sci. U.S.A. (in press)]. The spectroscopic data are interpreted on the basis of a protein structural model obtained via the homology with the major antenna complex LHCII [Kuhlbrandt, W., Wang, D. N., and Fujiyoshi, Y. (1994) Nature 367, 614-621]. The results allow us to determine the orientation of six chromophores within the protein structure. The orientations of the two remaining chromophores are inferred by considering the symmetry properties of CP29 and fitting steady state absorption and linear dichroism spectra by independent chlorophyll spectral forms. As a consequence, four "mixed" sites with different chlorophyll a and b binding affinities are identified in CP29. Geometrical data and the Förster mechanism for energy transfer suggest that excitation energy equilibrates rapidly among chlorophyll "pure" sites while energy preferentially flows outward from chlorophyll "mixed" sites. The orientation of the dipole moments of two chlorophyll molecules symmetrically located at the center of the protein and parallel to the carotenoid transition vectors suggests a role in energy transfer from xanthophyll to chlorophyll.In higher-plant chloroplasts, many pigment-binding proteins are inserted into the thylakoid membrane and organized into multisubunit complexes called photosystems. Photosystems (PS) 1 catalyze light absorption, the use of the excitation energy in transmembrane electron transport leading to the synthesis of ATP and NADPH. PS I and II are both composed of a chlorophyll a binding core complex and a chlorophyll a and b binding antenna. A detailed understanding of energy transfer processes in antenna and reaction centers requires knowledge of the distances between chromophores, of the mutual orientation between dipole transitions, and of the absorption and fluorescence energy levels and their distribution within the photosystems. In the case of PSII, considerable insight has been obtained from the topological organization of subunits (1-3) and from their spectral form decomposition (4, 5). Elucidation of the major antenna complex LHCII structure to 3.4 Å resolution (6) showed that many of the binding site environments are chemically distinct and that nearest-neighbor chlorophylls (Chl) are spaced 9-13 Å apart (center-center distance). The orientation of electronic transition dipole moments of the chromophores cannot yet be obtained from structural data, although linear dichrois...

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Section: Cp29 Structuralmentioning

confidence: 98%

“…The last two columns report the area under absorption and linear dichroism difference spectra after normalization. for Chl b (38,39). Two other values of 110°and 119°for Chl a and Chl b, respectively, must also be considered because of the two possible faces of a Chl.…”

Section: Cp29 Structuralmentioning

confidence: 99%

Orientation of Chlorophyll Transition Moments in the Higher-Plant Light-Harvesting Complex CP29

et al. 1999

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“…[2]). Figure 2 illustrates that the most probable normalized Q y electronic tdm vector is (x/y/z) = (0.19/0.98/ 0.07); this vector is also depicted in Figure 1 [2] a Q y angle of 708 with the x-axis, and for Chl a in nitrocellulose films [3] an angle of (105 AE 2)8 with the x-axis. Note that these determinations could not give information if the Q y tdm makes an angle with the X-Y plane, nor could they in principle distinguish between the angles 908 AE V with respect to the axis of orientation.…”

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confidence: 93%

Determining the Three‐Dimensional Electronic Transition Dipole Moment Orientation: Influence of an Isomeric Mixture

et al. 2010

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A new mixed experimental and theoretical approach for determining the exact three-dimensional orientation of electronic transition dipole moments (tdms) within the molecular frame is discussed. Results of applying this method on Chlorophyll a and the dye Coumarin 314 (C314) are presented. For C314 the possible influence of a mixture of E- and Z-isomers in the sample on the determined electronic tdm is investigated. Moreover, the robustness of the method is investigated with the C314 data.

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“…During the 1980s to 1990s, many new experiments [63,[69][70][71] were performed and interpreted in terms of the 'modern' assignment (ii), and this was backed up by density functional theory (DFT) calculations identifying that the þ2150 cm À1 band was an absorption named S 3 not anticipated by the Gouterman 4-orbital model and therefore never previously considered. [72,73] So in 2000 the situation again seemed clear, with the 'modern' assignment replacing the 'traditional' Gouterman one.…”

mentioning

confidence: 99%

“…[69] Based on my previous experience applying the methods of Craig and Ross to benzene and naphthalene, I was confident that appropriate calculations would interpret all spectra and resolve the issues. I wrote a much enhanced version of the complete neglect of differential overlap (CNDO) code of Del Bene and Jaffè [74] including expansion to include intermediate neglect of differential overlap (INDO) [75] and multi-reference configuration interaction (MRCI).…”

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confidence: 99%

Putting David Craig’s Legacy to Work in Nanotechnology and Biotechnology

Reimers¹

2016

Aust. J. Chem.

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left us with a lasting legacy concerning basic understanding of chemical spectroscopy and bonding. This is expressed in terms of some of the recent achievements of my own research career, with a focus on integration of Craig's theories with those of Noel Hush to solve fundamental problems in photosynthesis, molecular electronics (particularly in regard to the molecules synthesized by Maxwell Crossley), and self-assembled monolayer structure and function. Reviewed in particular is the relation of Craig's legacy to: the 50-year struggle to assign the visible absorption spectrum of arguably the world's most significant chromophore, chlorophyll; general theories for chemical bonding and structure extending Hush's adiabatic theory of electron-transfer processes; inelastic electron-tunnelling spectroscopy (IETS); chemical quantum entanglement and the Penrose-Hameroff model for quantum consciousness; synthetic design strategies for NMR quantum computing; Gibbs free-energy measurements and calculations for formation and polymorphism of organic self-assembled monolayers on graphite surfaces from organic solution; and understanding the basic chemical processes involved in the formation of gold surfaces and nanoparticles protected by sulfur-bound ligands, ligands whose form is that of Au 0 -thiyl rather than its commonly believed Au I -thiolate tautomer.

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LINEAR DICHROISM(250–700 nm) OF CHLOROPHYLL a AND PHEOPHYTIN a ORIENTED IN A LAMELLAR PHASE OF GLYCERYLMONOOCTANOATE/H₂O. CHARACTERIZATION OF ELECTRONIC TRANSITIONS

Cited by 97 publications

References 37 publications

Orientation of Chlorophyll Transition Moments in the Higher-Plant Light-Harvesting Complex CP29

Orientation of Chlorophyll Transition Moments in the Higher-Plant Light-Harvesting Complex CP29

Determining the Three‐Dimensional Electronic Transition Dipole Moment Orientation: Influence of an Isomeric Mixture

Putting David Craig’s Legacy to Work in Nanotechnology and Biotechnology

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