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Structural and Functional Hierarchy in Photosynthetic Energy Conversion-from Molecules to Nanostructures.

Szabó T, Magyar M, Hajdu K, Dorogi M, Nyerki E, Tóth T, Lingvay M, Garab G, Hernádi K, Nagy L - Nanoscale Res Lett (2015)

Bottom Line: Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials.It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure.This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics and Informatics, University of Szeged, Rerrich B. tér 1., H-6721, Szeged, Hungary. tiberatosz@gmail.com.

ABSTRACT
Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an electronic interaction between the protein and the inorganic carrier matrices. This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

No MeSH data available.


Related in: MedlinePlus

Change of the fluorescence intensity of a pH-sensitive dye (pyranine) during the photocycle of the RC. Fluorescence increase indicates pH increase inside the liposomes. Light is switched on and off, as indicated by the arrows. The effect of the protonophore gramicidin (gram) is also shown. Insert: Schematic representation of the RC turnover photocycle. Upon excitation by light P/P+//Q/Q- redox pair is created. The P/P+ couple is connected to cytochrome c2+/ cytochrome c3+ turnover on the donor side. The acceptor side is reset by the release of doubly reduced (and protonated) quinone and binding of the oxidized one to the RC. During the whole photocycle DpH is created
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Fig5: Change of the fluorescence intensity of a pH-sensitive dye (pyranine) during the photocycle of the RC. Fluorescence increase indicates pH increase inside the liposomes. Light is switched on and off, as indicated by the arrows. The effect of the protonophore gramicidin (gram) is also shown. Insert: Schematic representation of the RC turnover photocycle. Upon excitation by light P/P+//Q/Q- redox pair is created. The P/P+ couple is connected to cytochrome c2+/ cytochrome c3+ turnover on the donor side. The acceptor side is reset by the release of doubly reduced (and protonated) quinone and binding of the oxidized one to the RC. During the whole photocycle DpH is created

Mentions: By externally added donors (e.g. cytochrome c2) and acceptors (ubiquinone, UQ), conditions for the continuous turnover of the photocycle and the possibility of building up p.m.f. can be warranted. The change in the pH can be monitored by pH-sensitive fluorescent dyes which are sensitive to specific ionophores, like gramicidin, which eliminates the transmembrane proton gradient (Fig. 5, [36]).Fig. 5


Structural and Functional Hierarchy in Photosynthetic Energy Conversion-from Molecules to Nanostructures.

Szabó T, Magyar M, Hajdu K, Dorogi M, Nyerki E, Tóth T, Lingvay M, Garab G, Hernádi K, Nagy L - Nanoscale Res Lett (2015)

Change of the fluorescence intensity of a pH-sensitive dye (pyranine) during the photocycle of the RC. Fluorescence increase indicates pH increase inside the liposomes. Light is switched on and off, as indicated by the arrows. The effect of the protonophore gramicidin (gram) is also shown. Insert: Schematic representation of the RC turnover photocycle. Upon excitation by light P/P+//Q/Q- redox pair is created. The P/P+ couple is connected to cytochrome c2+/ cytochrome c3+ turnover on the donor side. The acceptor side is reset by the release of doubly reduced (and protonated) quinone and binding of the oxidized one to the RC. During the whole photocycle DpH is created
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4666181&req=5

Fig5: Change of the fluorescence intensity of a pH-sensitive dye (pyranine) during the photocycle of the RC. Fluorescence increase indicates pH increase inside the liposomes. Light is switched on and off, as indicated by the arrows. The effect of the protonophore gramicidin (gram) is also shown. Insert: Schematic representation of the RC turnover photocycle. Upon excitation by light P/P+//Q/Q- redox pair is created. The P/P+ couple is connected to cytochrome c2+/ cytochrome c3+ turnover on the donor side. The acceptor side is reset by the release of doubly reduced (and protonated) quinone and binding of the oxidized one to the RC. During the whole photocycle DpH is created
Mentions: By externally added donors (e.g. cytochrome c2) and acceptors (ubiquinone, UQ), conditions for the continuous turnover of the photocycle and the possibility of building up p.m.f. can be warranted. The change in the pH can be monitored by pH-sensitive fluorescent dyes which are sensitive to specific ionophores, like gramicidin, which eliminates the transmembrane proton gradient (Fig. 5, [36]).Fig. 5

Bottom Line: Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials.It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure.This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics and Informatics, University of Szeged, Rerrich B. tér 1., H-6721, Szeged, Hungary. tiberatosz@gmail.com.

ABSTRACT
Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an electronic interaction between the protein and the inorganic carrier matrices. This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

No MeSH data available.


Related in: MedlinePlus