Flash‐photolysis studies of the electron transfer from genetically modified spinach plastocyanin to photosystem I

Nordling, Margareta; Sigfridsson, Kalle; Young, Stanley; Lundberg, Lennart; Hansson, Örjan

doi:10.1016/0014-5793(91)81313-w

Cited by 91 publications

(85 citation statements)

References 18 publications

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“…These small domains of negatively charged amino acids are thought to mediate the interaction of plastocyanin with Cyt/and P700 from PSI (Beoku-Betts et al, 1983). Synechococcus also lacks the hydrophobic patch conserved in algae and higher plants surrounding the Cu ligand His-87, a domain possibly also involved with PSI interaction (Nordling et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

Inactivation of the petE Gene for Plastocyanin Lowers Photosynthetic Capacity and Exacerbates Chilling-Induced Photoinhibition in the Cyanobacterium Synechococcus

Clarke

Campbell

1996

Plant Physiology

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Section: Discussionmentioning

confidence: 99%

Inactivation of the petE Gene for Plastocyanin Lowers Photosynthetic Capacity and Exacerbates Chilling-Induced Photoinhibition in the Cyanobacterium Synechococcus

Clarke

Campbell

1996

Plant Physiology

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“…Using the vector pUGlOlt, (Nordling et al, 1991), the mutant Gly8Asp was constructed using the polymerase chain reaction as reported in Landt et al (1990), with the modifications described in Nordling et al (1991). After sequencing on an Automated Laser Fluorescence (ALF) sequencer, the correct clone was expressed under the lac promoter, as described in Ejdeback et al (1997).…”

Section: Expression and Purificationmentioning

confidence: 99%

Crystal structure of spinach plastocyanin at 1.7 Å resolution

et al. 1998

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The crystal structure of plastocyanin from spinach has been determined using molecular replacement, with the structure of plastocyanin from poplar as a search model. Successful crystallization was facilitated by site-directed mutagenesis in which residue Gly8 was substituted with Asp. The region around residue 8 was believed to be too mobile for the wild-type protein to form crystals despite extensive screening. The current structure represents the oxidized plastocyanin, copper (II), at low pH (-4.4). In contrast to the similarity in the core region as compared to its poplar counterpart, the structure shows some significant differences in loop regions. The most notable is the large shift of the 59-61 loop where the largest shift is 3.0 for the C, atom of Glu59. This results in different patterns of electrostatic potential around the acidic patches for the two proteins.

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“…Digitonin-solubilized PSI particles were prepared as described (10) and stored under liquid nitrogen until used. The preparation contains 240 chlorophylls per P700 and is highly competent in plastocyanin photooxidation (11). When complemented with plastocyanin, ferredoxin, and ferredoxin-NADP+ oxidoreductase, the rate of NADP+ photoreduction amounts to 240 ,tmol of NADPH per h per mg of chlorophyll.…”

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confidence: 99%

Electrogenic light reactions in photosystem I: resolution of electron-transfer rates between the iron-sulfur centers.

Sigfridsson

Hansson

Brzezinski

1995

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

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Flash-induced voltage changes (electrogenic events) in photosystem I particles from spinach, oriented in a phospholipid layer, have been studied at room temperature on a time scale ranging from 1 ,us to several seconds. A phospholipid layer containing photosystem I particles was adsorbed to a Teflon film separating two aqueous compartments. Voltage changes were measured across electrodes immersed in the compartments. In the absence of added electron donors and acceptors, a multiphasic voltage increase, associated with charge separation, was followed by a decrease, associated with charge recombination. Several kinetic phases were resolved: a rapid (<1 ,us) increase, ascribed to electron transfer from the primary electron donor P700 to the ironsulfur electron acceptor FB, was followed by a slower, biphasic increase with time constants of 30 and 200 ,is. The 30-,us phase is assigned to electron transfer from FB to the ironsulfur center FA. The voltage decrease had a time constant of 90 ms, ascribed to charge recombination from FA to P700. Upon chemical prereduction of FA and FB the 30-and 200-,us phases disappeared and the decay time constant was accelerated to 330 pus, assigned to charge recombination from the phylloquinone electron acceptor (A1) or the iron-sulfur center Fx to P700.The photosystem I (PSI) reaction center is a membrane-bound protein complex, which converts light energy to redox energy.The spinach complex consists of 2 large ("80 kDa) and at least 10 smaller (5-20 kDa) subunits, which bind a number of cofactors associated with the conversion process. The absorption of light by one of -200 antenna chlorophyll molecules is followed by a rapid migration of the excitation energy to the chlorophyll primary electron donor, P700, and an electron transfer is then brought about between P700 and the chlorophyll primary electron acceptor Ao. The sequence and kinetics of the electron-transfer reactions between the different cofactors have been investigated by a number of spectroscopic techniques, including flash-induced optical and electron paramagnetic resonance (EPR) spectroscopy. The details of the electron-transfer reactions between the Fe-S centers are, however, largely unknown. This is so because the optical spectra of the Fe-S centers are nearly identical and, although they can be distinguished with EPRThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. spectroscopy, such studies can be made only at low temperatures (<40 K) since their EPR spectra are too broad at higher temperatures.In this study, we have used a different approach. PSI particles were oriented in a phospholipid layer adsorbed to a Teflon film, and light-induced electrogenic events were measured. This technique has previously been used with bacteriorhodopsin (5) and with reaction centers from purple bacteria (6), from PSII (7), and cytochrome c oxidase (8). After pulsed illu...

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Flash‐photolysis studies of the electron transfer from genetically modified spinach plastocyanin to photosystem I

Cited by 91 publications

References 18 publications

Inactivation of the petE Gene for Plastocyanin Lowers Photosynthetic Capacity and Exacerbates Chilling-Induced Photoinhibition in the Cyanobacterium Synechococcus

Inactivation of the petE Gene for Plastocyanin Lowers Photosynthetic Capacity and Exacerbates Chilling-Induced Photoinhibition in the Cyanobacterium Synechococcus

Crystal structure of spinach plastocyanin at 1.7 Å resolution

Electrogenic light reactions in photosystem I: resolution of electron-transfer rates between the iron-sulfur centers.

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