Efficient energy transfer from the long-wavelength antenna chlorophylls to P700 in photosystem I complexes from Spirulina platensis

Shubin, Vladimir; Bezsmertnaya, I. N.; Karapetyan, N. V.

doi:10.1016/1011-1344(95)07173-y

Cited by 67 publications

(54 citation statements)

References 24 publications

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“…Characterization of Isolated PS I-Whereas several reports deal with the spectral properties of PS I from S. platensis (12,16,20), only limited information is available on the biochemical level (9, 31). Here we show that PS I from S. platensis contains the same major subunits (PsaA, -B, -C, -D, -E, -F, and -L) that were already found in Synechocystis (24) and Synechococcus (32).…”

Section: Discussionmentioning

confidence: 99%

In Vitro Oligomerization of a Membrane Protein Complex

Kruip

Karapetyan

Терехова

et al. 1999

Journal of Biological Chemistry

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Many membrane proteins can be isolated in different oligomeric forms. Photosystem I (PSI), for example, exists in cyanobacteria either as a monomeric or as a trimeric complex. Neither the factors responsible for the specific trimerization process nor its biological role are known at present. In the filamentous cyanobacterium Spirulina platensis, trimers in contrast to monomers show chlorophyll fluorescence emission at 760 nm. To investigate the oligomerization process as well as the nature of the long wavelength chlorophylls, we describe here an in vitro reconstitution procedure to assemble trimeric PS I from isolated purified PS I monomers. Monomers (and trimers) were extracted from S. platensis with n-dodecyl ␤-D-maltoside and further purified by perfusion chromatography steps. The isolated complexes had the same polypeptide composition as other cyanobacteria (PsaA-PsaF and PsaI-PsaM), as determined from high resolution gels and immunoblotting. They were incorporated into proteoliposomes, which had been prepared by the detergent absorption method, starting from a phosphatidylcholine:phosphatidic acid mixture solubilized by octylglucoside. After the addition of monomeric PS I (lipid:chlorophyll, 25:1), octylglucoside was gradually removed by the stepwise addition of Biobeads. The 77 K fluorescence emission spectrum of these proteoliposomes displays a long wavelength emission at 760 nm that is characteristic of PS I trimers, which indicates for the first time the successful in vitro reconstitution of PS I trimers. In addition, a high performance liquid chromatography analysis of complexes extracted from these proteoliposomes confirms the formation of structural trimers. We also could show with this system 1) that at least one of the stromal subunits PsaC, -D, and -E is necessary for trimer formation and 2) that the extreme long wavelength emitting chlorophyll is formed as a result of trimer formation.

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Section: Discussionmentioning

confidence: 99%

In Vitro Oligomerization of a Membrane Protein Complex

Kruip

Karapetyan

Терехова

et al. 1999

Journal of Biological Chemistry

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“…Long wavelength absorbing chlorophylls (Chls) have been proposed to focus excitation energy to the reaction centre of PS I (Shubin et al 1995), to be an intermediate energy trap (Woolfe et al 1994), to facilitate light absorption (Trissl 1993) and to serve a photoprotective purpose for PS I . The trimerisation of PS I in vivo has been suggested to mediate state transitions in cyanobacteria (Kruip et al 1994).…”

Section: Introductionmentioning

confidence: 99%

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Mangels

Kruip

Berry

et al. 2002

Photosynthesis Research

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Photosystem I from the unusual cyanobacterium Gloeobacter violaceus Mangels, D.; Kruip, J.; Berry, S.; Rögner, M.; Boekema, E.J.; Koenig, F. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Key words: antenna system, electron microscopy, fluorescence, light harvesting, photosynthesis, plasma membrane AbstractPhotosystem I (PS I) from the primitive cyanobacterium Gloeobacter violaceus has been purified and characterised. Despite the fact that the isolated complexes have the same subunit composition as complexes from other cyanobacteria, the amplitude of flash-induced absorption difference spectra indicates a much bigger antenna size with about 150 chlorophylls per P700 as opposed to the usual 90. Image analysis of the PS I preparation from Gloeobacter reveals that the PS I particles exist both in a trimeric and in a monomeric form and that their size and shape closely resembles other cyanobacterial PS I particles. However, the complexes exhibit a higher molecular weight as could be shown by gel filtration. The preparation contains novel polypeptides not related to known Photosystem I subunits. The N-terminal sequence of one of those polypeptides has been determined and reveals no homology to known or hypothetical proteins. Immunoblotting shows a cross-reaction of three of the polypeptide bands with an antibody raised against the major LHC from the diatom Cyclotella cryptica. Electron microscopy reveals a novel T-shaped complex which has never been observed in any other cyanobacterial PS I preparation. 77 K spectra of purified PS I show an extreme blue-shift of the fluorescence emission, indicating an unusual organisation of the PS I antenna system in Gloeobacter.Abbreviations: PS -photosystem; Chl -chlorophyll; DM -dodecyl-β-D-maltoside; ECL -enhanced chemiluminescence; HPLC -high performance liquid chromatography; IEC -ion exchange chromatography; GF -gel filtration; LHC I -light harvesting complex associated with Photosystem I; P700 -primary electron donor of photosystem I; SDS -sodium dodecyl sulfate; SQDG -sulfoquinovosyl diacylglycerol; PAGE -polyacrylamide gel electrophoresis; F760 (F730) -fluorescence band with maximal emission at 760 nm (730 nm)

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“…The physiological importance of the PSI trimers is unknown. Some authors suggested that such oligomers can protect the PSI RCs against light stress by permitting radiationless dissipation of excess energy into heat (Mukerji and Sauer, 1989;Karapetyan et al, 1999), that red chlorophylls (Chls) can funnel light energy to P700 (van Grondelle et al, 1994;Shubin et al, 1995) as well as increase the cross section of light absorption (Trissl, 1993). Earlier the effect of lipids on the formation of PSI RCs was suggested by measuring the effect of lipids on the PSI trimer formation (Kruip et al, 1999).…”

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Phosphatidylglycerol Is Essential for Oligomerization of Photosystem I Reaction Center

et al. 2004

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Our earlier studies with the pgsA mutant of Synechocystis PCC6803 demonstrated the important role of phosphatidylglycerol (PG) in PSII dimer formation and in electron transport between the primary and secondary electron-accepting plastoquinones of PSII. Using a long-term depletion of PG from pgsA mutant cells, we could induce a decrease not only in PSII but also in PSI activity. Simultaneously with the decrease in PSI activity, dramatic structural changes of the PSI complex were detected. A 21-d PG depletion resulted in the degradation of PSI trimers and concomitant accumulation of monomer PSI. The analyses of PSI particles isolated by MonoQ chromatography showed that, following the 21-d depletion, PSI trimers were no longer detectable in the thylakoid membranes. Immunoblot analyses revealed that the PSI monomers accumulating in the PG-depleted mutant cells do not contain PsaL, the protein subunit thought to be responsible for the trimer formation. Nevertheless, the trimeric structure of PSI reaction center could be restored by readdition of PG, even in the presence of the protein synthesis inhibitor lincomycin, indicating that free PsaL was present in thylakoid membranes following the 21-d PG depletion. Our data suggest an indispensable role for PG in the PsaL-mediated assembly of the PSI reaction center.Phosphatidylglycerol (PG) is an integral component of photosynthetic membranes. PG molecules are important for both the formation and functioning of photosynthetic apparatus. In cyanobacterial cells, PG is the only representative of the phospholipid family (Wada and Murata, 1998), and the majority of PG molecules are localized in the thylakoid membranes that are the site of oxygenic electron transport. Photosynthesis is the basic energy source of cyanobacteria and generally for photosynthetic organisms. The availability of the complete genomic sequence of Synechocystis PCC6803 (Kaneko et al., 1996) opened the way for studying the structural and functional roles of PG via molecular genetic approaches. The pgsA gene encoding PG phosphate synthase was inactivated in Synechocystis PCC6803 cells by inserting a kanamycin resistance gene cassette (Hagio et al., 2000). Maintenance of the recently generated pgsA mutant strain requires exogenously supplied PG. A 40% decrease in photosynthetic oxygen-evolving activity could be detected following a 3-d depletion of PG, which resulted in an approximately 50% decrease in the amount of PG molecules in the cellular membranes. The photosynthetic processes, as measured by fluorescence induction in the PG-depleted cells, slowed down, and a perturbation of the surroundings of the secondary quinone acceptor (Q B ) was observed (Gombos et al., 2002). This perturbation was similar to the effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), which can block electron transport between primary quinone acceptor (Q A ) and Q B . Additionally, Fragata et al. (1991) demonstrated that in isolated barley (Hordeum vulgare) PSII particles, oxygen-evolving activity strongly depends on the pr...

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Efficient energy transfer from the long-wavelength antenna chlorophylls to P700 in photosystem I complexes from Spirulina platensis

Cited by 67 publications

References 24 publications

In Vitro Oligomerization of a Membrane Protein Complex

In Vitro Oligomerization of a Membrane Protein Complex

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Phosphatidylglycerol Is Essential for Oligomerization of Photosystem I Reaction Center

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