Distance and Potential Dependence of Charge Transport Through the Reaction Center of Individual Photosynthetic Complexes

Manuel López-Ortiz, Ricardo A. Zamora, Marina Inés Giannotti, Chen Hu, Roberta Croce, Pau Gorostiza*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

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Abstract

Charge separation and transport through the reaction center of photosystem I (PSI) is an essential part of the photosynthetic electron transport chain. A strategy is developed to immobilize and orient PSI complexes on gold electrodes allowing to probe the complex's electron acceptor side, the chlorophyll special pair P700. Electrochemical scanning tunneling microscopy (ECSTM) imaging and current–distance spectroscopy of single protein complex shows lateral size in agreement with its known dimensions, and a PSI apparent height that depends on the probe potential revealing a gating effect in protein conductance. In current–distance spectroscopy, it is observed that the distance-decay constant of the current between PSI and the ECSTM probe depends on the sample and probe electrode potentials. The longest charge exchange distance (lowest distance-decay constant β) is observed at sample potential 0 mV/SSC (SSC: reference electrode silver/silver chloride) and probe potential 400 mV/SSC. These potentials correspond to hole injection into an electronic state that is available in the absence of illumination. It is proposed that a pair of tryptophan residues located at the interface between P700 and the solution and known to support the hydrophobic recognition of the PSI redox partner plastocyanin, may have an additional role as hole exchange mediator in charge transport through PSI.
Original languageEnglish
Article number2104366
Pages (from-to)1-9
Number of pages9
JournalSmall
Volume18
Issue number7
Early online date7 Dec 2021
DOIs
Publication statusPublished - 17 Feb 2022

Bibliographical note

Funding Information:
M.L.-O. and R.A.Z. contributed equally to this work. This research received funding from the European Union Research and Innovation Programme Horizon 2020 ? HBP SG3 (945539), DEEPER (ICT-36-2020-101016787), European Research ERA-Net SynBio programme (Mod- ulightor project), and financial support from Agency for Management of University and Research Grants (CERCA Pro- gramme; 2017-SGR-1442 project), Ministry of Economy and Competitive- ness (MINECO)/FEDER (Grant CTQ2016- 80066-R, the Fundaluce foundation, the Commission for Uni- versities and Research of the Department of Innovation, Universities, and Enterprise of the Generalitat de Catalunya -AGAUR- (IU16-011508) and co- financed by the European Union Regional Development Fund within the framework of the ERDF/FEDER Operational Program of Catalonia 2014? 2020 with a grant of 50% of total eligible cost. R.Z. was supported by National Agency for Research and Development (ANID)/Scholarship Program POSTDOCTORADO BECAS CHILE/2018 ? 74190117.

Funding Information:
M.L.‐O. and R.A.Z. contributed equally to this work. This research received funding from the European Union Research and Innovation Programme Horizon 2020 – HBP SG3 (945539), DEEPER (ICT‐36‐2020‐101016787), European Research ERA‐Net SynBio programme (Mod‐ ulightor project), and financial support from Agency for Management of University and Research Grants (CERCA Pro‐ gramme; 2017‐SGR‐1442 project), Ministry of Economy and Competitive‐ ness (MINECO)/FEDER (Grant CTQ2016‐ 80066‐R, the Fundaluce foundation, the Commission for Uni‐ versities and Research of the Department of Innovation, Universities, and Enterprise of the Generalitat de Catalunya ‐AGAUR‐ (IU16‐011508) and co‐ financed by the European Union Regional Development Fund within the framework of the ERDF/FEDER Operational Program of Catalonia 2014– 2020 with a grant of 50% of total eligible cost. R.Z. was supported by National Agency for Research and Development (ANID)/Scholarship Program POSTDOCTORADO BECAS CHILE/2018 – 74190117.

Publisher Copyright:
© 2021 Wiley-VCH GmbH

Funding

M.L.-O. and R.A.Z. contributed equally to this work. This research received funding from the European Union Research and Innovation Programme Horizon 2020 ? HBP SG3 (945539), DEEPER (ICT-36-2020-101016787), European Research ERA-Net SynBio programme (Mod- ulightor project), and financial support from Agency for Management of University and Research Grants (CERCA Pro- gramme; 2017-SGR-1442 project), Ministry of Economy and Competitive- ness (MINECO)/FEDER (Grant CTQ2016- 80066-R, the Fundaluce foundation, the Commission for Uni- versities and Research of the Department of Innovation, Universities, and Enterprise of the Generalitat de Catalunya -AGAUR- (IU16-011508) and co- financed by the European Union Regional Development Fund within the framework of the ERDF/FEDER Operational Program of Catalonia 2014? 2020 with a grant of 50% of total eligible cost. R.Z. was supported by National Agency for Research and Development (ANID)/Scholarship Program POSTDOCTORADO BECAS CHILE/2018 ? 74190117. M.L.‐O. and R.A.Z. contributed equally to this work. This research received funding from the European Union Research and Innovation Programme Horizon 2020 – HBP SG3 (945539), DEEPER (ICT‐36‐2020‐101016787), European Research ERA‐Net SynBio programme (Mod‐ ulightor project), and financial support from Agency for Management of University and Research Grants (CERCA Pro‐ gramme; 2017‐SGR‐1442 project), Ministry of Economy and Competitive‐ ness (MINECO)/FEDER (Grant CTQ2016‐ 80066‐R, the Fundaluce foundation, the Commission for Uni‐ versities and Research of the Department of Innovation, Universities, and Enterprise of the Generalitat de Catalunya ‐AGAUR‐ (IU16‐011508) and co‐ financed by the European Union Regional Development Fund within the framework of the ERDF/FEDER Operational Program of Catalonia 2014– 2020 with a grant of 50% of total eligible cost. R.Z. was supported by National Agency for Research and Development (ANID)/Scholarship Program POSTDOCTORADO BECAS CHILE/2018 – 74190117.

FundersFunder number
Agency for Management of University2017-SGR-1442
Commission for Uni- versities and Research of the Department of Innovation
Commission for Uni‐ versities and Research of the Department of Innovation
DEEPER
Enterprise of the Generalitat de Catalunya ‐AGAUR
European Union Research and Innovation Programme Horizon 2020ICT‐36‐2020‐101016787, 945539
Fundaluce foundation
Agenția Națională pentru Cercetare și Dezvoltare
Generalitat de Catalunya
Federación Española de Enfermedades RarasCTQ2016‐ 80066‐R
Agència de Gestió d'Ajuts Universitaris i de RecercaIU16‐011508
Ministerio de Economía y Competitividad
European Regional Development Fund
Agencia Nacional de Investigación y DesarrolloCHILE/2018 – 74190117

    Keywords

    • current distance decay spectroscopy
    • electrochemical scanning tunneling microscopy (ECSTM)
    • photosystem I
    • protein electron transfer
    • single molecules

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