CHLOROPHYLL BINDING PROTEINS WITH ANTENNA FUNCTION IN HIGHER PLANTS and GREEN ALGAE

Bassi, Roberto; Rigoni, Fernanda; Giacometti, Giorgio M.

doi:10.1111/j.1751-1097.1990.tb08457.x

Cited by 158 publications

(59 citation statements)

References 203 publications

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“…The use of LHCII as an experimental model is, however, hampered for a number of reasons. First, LHCII is a trimer, and the interactions between chromophores belonging to neighboring monomers are strong and modify the spectral properties of the system (42)(43)(44). Second, LHCII binds 12 Chl molecules per polypeptide and three xanthophylls, while only eight Chl binding sites and two xanthophyll binding sites have been identified so far in the protein structure.…”

Section: Discussionmentioning

confidence: 99%

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: Discussionmentioning

confidence: 99%

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

et al. 1999

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“…The two LHC I clones each contain five to six histidine residues in the mature protein region, as compared with three histidine residues in the LHC IIb protein. This number of histidine residues would therefore be insufficient to form ligands with each of the 10 to 13 Chl molecules that are thought to be bound by a single Chl a/bbinding apoprotein (Bassi et al, 1990). There are, however, in both proteins, sufficient quantities of asparagine and glutamine residues that could also coordinate the Chl molecules (Peter and Thornber, 1988).…”

Section: Cag Gcg Acg Tac Ctg Cgc M C Ccg Gtg Ccc Tgg Ggc M C Ctg Ccg mentioning

confidence: 99%

Light-Induced Biogenesis of Light-Harvesting Complex I (LHC I) during Chloroplast Development in Barley (Hordeum vulgare) (Studies Using cDNA Clones of the 21- and 20-Kilodalton LHC I Apoproteins)

1993

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Higher plant thylakoid membranes contain several multiprotein complexes: PSI and 11, the chloroplast ATPase, and the Cyt b/f complex. Each of the two photosystems can be conceptually divided into a CC and an LHC, which functions solely to absorb photons and to transfer the energy to the CC. The CC is also involved in the entrapment of light energy and, in addition, contains the photochemical reaction center, the site of conversion of absorbed light energy into chemical energy. The LHCs of both photosystems contain several distinct pigment-protein complexes that function to

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“…The gels after electrophoresis were scanned photometrically at 430 nm using spectrophotometer equipped with a special device. The positions of Chl-protein complexes in gels were identified by estimating molecular mass using standard markers in parallel gel as well as, after cutting out the bands from gels, both by measuring lowtemperature fluorescence spectra [13] and by performing, in some cases, the denaturing electrophoresis.…”

Section: Methodsmentioning

confidence: 99%

Photosystem II associated carbonic anhydrase activity in higher plants is situated in core complex

et al. 2004

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The thylakoid membrane containing photosystem II (PSII membranes) from pea and wheat leaves catalyzed the reaction of CO 2 hydration with low rate, which increased after their incubation either with Triton X-100, up to Triton/chlorophyll ratio 1:1, or 1 M CaCl 2 . The presence of the inhibitor of CAs, p-aminomethylbenzensulfonamide (mafenide), at the start line in the course of electrophoresis of PSII membranes solubilized by n-dodecyl-b-maltoside (DM) decreased the amount of PSII core complex in the gel. The elution of PSII core complex from the column with immobilized mafenide occurred only either by mafenide or another inhibitor of CAs, ethoxyzolamide. The above results led to a conclusion that membrane-bound CA activity associated with PSII is situated in the core complex.

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CHLOROPHYLL BINDING PROTEINS WITH ANTENNA FUNCTION IN HIGHER PLANTS and GREEN ALGAE

Cited by 158 publications

References 203 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

Light-Induced Biogenesis of Light-Harvesting Complex I (LHC I) during Chloroplast Development in Barley (Hordeum vulgare) (Studies Using cDNA Clones of the 21- and 20-Kilodalton LHC I Apoproteins)

Photosystem II associated carbonic anhydrase activity in higher plants is situated in core complex

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