Species Dependence of the Redox Potential of the Primary Electron Donor P700 in Photosystem I of Oxygenic Photosynthetic Organisms Revealed by Spectroelectrochemistry

Nakamura, Akimasa; Suzawa, Tomoyuki; Kato, Yuki; Watanabe, Tadashi

doi:10.1093/pcp/pcr034

Cited by 45 publications

(30 citation statements)

References 47 publications

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“…The data were similarly described by other groups for bc 1 complexes from other organisms (Ritter et al , 2003 ;Iwaki et al , 2005 ). The use of the UV/VIS range for the study of the redox properties of membrane proteins is now well established; recent examples include the study of the PSII and different enzymes from respiration, such as complex II (Christenson et al , 2008 ;Kato et al , 2009 ;Nakamura et al , 2011 ).…”

Section: Uv/vis Spectroscopymentioning

confidence: 59%

Recent advances in the electrochemistry and spectroelectrochemistry of membrane proteins

Melin

Hellwig

2013

Biological Chemistry

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Abstract:Integral membrane proteins are encountered in fundamental natural processes, such as photosynthesis and respiration. The relation between the structure of the proteins and their function and dynamics are still not clear in most cases. Once fully understood, these processes could ultimately help researchers to develop alternative methods for producing energy, either from light or biomass. They could also lead to more efficient antibiotics, which would selectively inhibit a specific membrane protein of pathogenic bacteria. Since the chemical reactions involved in both photosynthesis and respiration are redox reactions, electrochemical methods can play a considerable role in uncovering their mechanisms. The electrochemical characterization of membrane proteins is, however, quite challenging. An overview on the techniques used for the characterization of membrane proteins, including classical approaches such as voltammetry and spectroelectrochemistry, and recent developments, such as their combination with surface-enhanced techniques is given.

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Section: Uv/vis Spectroscopymentioning

confidence: 59%

Recent advances in the electrochemistry and spectroelectrochemistry of membrane proteins

Melin

Hellwig

2013

Biological Chemistry

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“…These values are similar to that obtained from experiment [53,54], and are the values used in our calculations. The midpoint potential of P700 (P700/P700 + ) in photosystem I for S6803 is close to +450 mV [23], and this is the number used in our calculations. The midpoint potentials of the cofactors that were assigned are shown in Figure 1.…”

Section: Application Of Non-adiabatic Et Theorymentioning

confidence: 84%

“…Edge-to-edge distances (in Å) between cofactors is represented by the dotted vertical lines. The established redox potentials for P700/P700 + [23], F X /F X  [24], F A /F A  and F B /F B  [25] are shown. The kinetic model used to simulate the light-induced population evolution of radical states in PSI at both 298 and 77 K is outlined.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Modeling electron transfer in photosystem I

Makita

Hastings

2016

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Nanosecond to millisecond time-resolved absorption spectroscopy has been used to study electron transfer processes in photosystem I particles from Synechocystis sp. PCC 6803 with eight different quinones incorporated into the A1 binding site, at both 298 and 77K. A detailed kinetic model was constructed and solved within the context of Marcus electron transfer theory, and it was found that all of the data could be well described only if the in situ midpoint potentials of the quinones fell in a tightly defined range. For photosystem I with phylloquinone incorporated into the A1 binding site all of the time-resolved optical data is best modeled when the in situ midpoint potential of phylloquinone on the A/B branch is -635/-690 mV, respectively. With the midpoint potential of the F(X) iron sulfur cluster set at -680 mV, this indicates that forward electron transfer from A(1)(-) to F(X) is slightly endergonic/exergonic on the A/B branch, respectively. Additionally, for forward electron transfer from A(1)(-) to F(X), on both the A and B branches the reorganization energy is close to 0.7 eV. Reorganization energies of 0.4 or 1.0 eV are not possible. For the eight different quinones incorporated, the same kinetic model was used, allowing us to establish in situ redox potentials for all of the incorporated quinones on both branches. A linear correlation was found between the in situ and in vitro midpoint potentials of the quinones on both branches.

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“…As such, the antenna system of PSI in drought-tolerant organisms could transfer light energy even under or after dry/light conditions. Because the redox potential of P700 is much lower than that of P680 in the PSII reaction center (Kato et al, 2009;Nakamura et al, 2011), the formation of reactive oxygen species and the chlorophyll triplet state are not as prominent in PSI. Thus, the long-lived oxidized form of P700 may be less harmful to surrounding microenvironments.…”

Section: Discussionmentioning

confidence: 99%

Ideal Osmotic Spaces for Chlorobionts or Cyanobionts Are Differentially Realized by Lichenized Fungi

Kosugi

Shizuma²,

Moriyama³

et al. 2014

Plant Physiology

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Lichens result from symbioses between a fungus and either a green alga or a cyanobacterium. They are known to exhibit extreme desiccation tolerance. We investigated the mechanism that makes photobionts biologically active under severe desiccation using green algal lichens (chlorolichens), cyanobacterial lichens (cyanolichens), a cephalodia-possessing lichen composed of green algal and cyanobacterial parts within the same thallus, a green algal photobiont, an aerial green alga, and a terrestrial cyanobacterium. The photosynthetic response to dehydration by the cyanolichen was almost the same as that of the terrestrial cyanobacterium but was more sensitive than that of the chlorolichen or the chlorobiont. Different responses to dehydration were closely related to cellular osmolarity; osmolarity was comparable between the cyanolichen and a cyanobacterium as well as between a chlorolichen and a green alga. In the cephalodium-possessing lichen, osmolarity and the effect of dehydration on cephalodia were similar to those exhibited by cyanolichens. The green algal part response was similar to those exhibited by chlorolichens. Through the analysis of cellular osmolarity, it was clearly shown that photobionts retain their original properties as free-living organisms even after lichenization.

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Species Dependence of the Redox Potential of the Primary Electron Donor P700 in Photosystem I of Oxygenic Photosynthetic Organisms Revealed by Spectroelectrochemistry

Cited by 45 publications

References 47 publications

Recent advances in the electrochemistry and spectroelectrochemistry of membrane proteins

Recent advances in the electrochemistry and spectroelectrochemistry of membrane proteins

Modeling electron transfer in photosystem I

Ideal Osmotic Spaces for Chlorobionts or Cyanobionts Are Differentially Realized by Lichenized Fungi

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