Bidirectional Electron Transfer in the Reaction Centre of Photosystem I

Santabarbara, Stefano; Galuppini, Luca; Casazza, Anna Paola

doi:10.1111/j.1744-7909.2010.00977.x

Cited by 34 publications

(74 citation statements)

References 94 publications

(185 reference statements)

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“…The D1 protein is rapidly cycled during illumination and disruption of D1 protein cycling or losses of D1 protein pools are central to the photoinhibition of photosynthesis (Nixon et al, 2005; reviewed by Nixon et al, 2010). One of the important proteins in the photosystem I (PSI) reaction centre is the Chl a binding core protein, PsaA (82-83 kDa;Hall & Rao 1999; reviewed by Santabarbara et al 2010). PSI is involved in linear electron transport as well as cyclic electron transfer around PSI.…”

Section: Introductionmentioning

confidence: 99%

Photosynthesis in relation to D1, PsaA and Rubisco in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae)

et al. 2012

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The aim of this study was to investigate photosynthetic differences between the marine, Norwegian Sea ecotype and the brackish, Bothnian Sea ecotype of F. vesiculosus and F. radicans and to see whether photosynthetic differences could be connected with the relative amounts of D1 protein (PSII), PsaA (PSI) protein and/or Rubisco. For this purpose, we tested if a higher photosynthetic maximum (P max ) in the Atlantic Ocean ecotype of F. vesiculosus relative to the Baltic Sea ecotype, and an increase of the P max in Baltic Sea ecotype of F. vesiculosus at higher salinity, could be due to an increase in the relative amounts of Rubisco. The proteins have been evaluated on a relative basis. Immunoblot signals showed that the amount of Rubisco was higher in both ecotypes of F. vesiculosus than in F. radicans, but no differences could be detected between the two ecotypes of F. vesiculosus. The results suggest an uneven photosystem protein stoichiometry in Fucus, with more of the PSI protein PsaA relative to the PSII protein D1. The difference in P max between the two ecotypes of F. vesiculosus might be related to the difficulties for the algae to adapt to the environment in Bothnian Sea.

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Section: Introductionmentioning

confidence: 99%

Photosynthesis in relation to D1, PsaA and Rubisco in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae)

et al. 2012

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“…In the microsecond time window, separated charges should be stabilized mainly in states Y Z *P 680 Q A -for PSII and P 700 ? F A /F B -for PSI or Fd -in the whole cells (Golbeck 1994;Nugent 1996;Brettel 1997;Diner and Babcock 1996;Hou et al 2001b;Santabarbara et al 2010). Contrary to previous interpretations, but in agreement with Hou et al (2001a, b), our results show that PSI-deficient mutants have lower ES efficiency (*50%) than PSII-deficient mutants (*80%).…”

Section: Discussionmentioning

confidence: 99%

Photosynthetic energy storage efficiency in Chlamydomonas reinhardtii, based on microsecond photoacoustics

et al. 2011

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Using a novel, pulsed micro-second time-resolved photoacoustic (PA) instrument, we measured thermal dissipation and energy storage (ES) in the intact cells of wild type (WT) Chlamydomonas reinhardtii, and mutants lacking either PSI or PSII reaction centers (RCs). On this time scale, the kinetic contributions of the thermal expansion component due to heat dissipation of absorbed energy and the negative volume change due to electrostriction induced by charge separation in each of the photosystems could be readily distinguished. Kinetic analysis revealed that PSI and PSII RCs exhibit strikingly different PA signals where PSI is characterized by a strong electrostriction signal and a weak thermal expansion component while PSII has a small electrostriction component and large thermal expansion. The calculated ES efficiencies at ~10 μs were estimated to be 80 ± 5 and 50 ± 13% for PSII-deficient mutants and PSI-deficient mutants, respectively, and 67 ± 2% for WT. The overall ES efficiency was positively correlated with the ratio of PSI to PSI + PSII. Our results suggest that the shallow excitonic trap in PSII limits the efficiency of ES as a result of an evolutionary frozen metabolic framework of two photosystems in all oxygenic photoautotrophs.

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“…the standard free energy difference . 0) for the former and favorable (standard free energy difference , 0) for the latter (Santabarbara et al, 2005a(Santabarbara et al, , 2010a. Such "functional asymmetry" in A 1A/B energetic properties appears to be qualitatively conserved in FN68.…”

Section: Pulsed Electron Paramagnetic Resonance Analysis Of the Psi Rmentioning

confidence: 95%

The Requirement for Carotenoids in the Assembly and Function of the Photosynthetic Complexes in Chlamydomonas reinhardtii

et al. 2012

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We have investigated the importance of carotenoids on the accumulation and function of the photosynthetic apparatus using a mutant of the green alga Chlamydomonas reinhardtii lacking carotenoids. The FN68 mutant is deficient in phytoene synthase, the first enzyme of the carotenoid biosynthesis pathway, and therefore is unable to synthesize any carotenes and xanthophylls. We find that FN68 is unable to accumulate the light-harvesting complexes associated with both photosystems as well as the RC subunits of photosystem II. The accumulation of the cytochrome b 6 f complex is also strongly reduced to a level approximately 10% that of the wild type. However, the residual fraction of assembled cytochrome b 6 f complexes exhibits single-turnover electron transfer kinetics comparable to those observed in the wild-type strain. Surprisingly, photosystem I is assembled to significant levels in the absence of carotenoids in FN68 and possesses functional properties that are very similar to those of the wild-type complex.

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Bidirectional Electron Transfer in the Reaction Centre of Photosystem I

Cited by 34 publications

References 94 publications

Photosynthesis in relation to D1, PsaA and Rubisco in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae)

Photosynthesis in relation to D1, PsaA and Rubisco in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae)

Photosynthetic energy storage efficiency in Chlamydomonas reinhardtii, based on microsecond photoacoustics

The Requirement for Carotenoids in the Assembly and Function of the Photosynthetic Complexes in Chlamydomonas reinhardtii

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