Bioelectrochemistry (Amsterdam, Netherlands)

1878-562X1272019JunBioelectrochemistry (Amsterdam, Netherlands)BioelectrochemistryElectrochemical characterization of LHCII on graphite electrodes - Potential-dependent photoactivation and arrangement of complexes.374837-4810.1016/j.bioelechem.2019.01.005S1567-5394(18)30372-4Light-dependent electrochemical properties of the light harvesting complexes of Photosystem II (LHCII) and the corresponding interactions with screen-printed graphite electrodes (GEs) are determined. No exogenous soluble redox mediators are used. LHCII isolated from spinach leaves are immobilized on GE by physical adsorption and through interactions with glutaraldehyde. Importantly, the insertion of LHCII into the pores of a GE is achieved by subjecting the electrode to specific potentials. Both trimeric and aggregated forms of LHCII located within the graphite layer retain their native structures. Voltammetric current peaks centred at ca. -230 and + 50 mV vs. Ag/AgCl (+94 and + 374 mV vs. NHE) limit the investigation of the reduction and oxidation processes of immobilized LHCII. An anodic photocurrent is generated in the LHCII-GE proportional to light intensity and can reach a value of 150 nA/cm². Light-dependent charge separation in LHCII followed by electron transfer to the GE occurs only at potentials of above -200 mV vs. Ag/AgCl (+124 mV vs. NHE). Our results illustrate the importance of the structural proximity of LHCII and GE for photocurrent generation.Copyright © 2019 Elsevier B.V. All rights reserved.PiotrowskaPaulinaPFaculty of Biology, Department of Metabolic Regulation, Institute of Biochemistry, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.ŁazickaMagdalenaMFaculty of Biology, Department of Metabolic Regulation, Institute of Biochemistry, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.Palińska-SaadiAdrianaABioanalytical Laboratory, Biological and Chemical Research Centre, University of Warsaw, Zwirki i Wigury 101, 02-089 Warsaw, Poland.PaterczykBohdanBFaculty of Biology, Laboratory of Electron and Confocal Microscopy, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.KowalewskaŁucjaŁFaculty of Biology, Department of Plant Anatomy and Cytology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.GrzybJoannaJFaculty of Biotechnology, Department of Biophysics, University of Wroclaw, F. Joliot-Curie 14a, 50-383 Wroclaw, Poland; Institute of Physics of the Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.Maj-ŻurawskaMagdalenaMBioanalytical Laboratory, Biological and Chemical Research Centre, University of Warsaw, Zwirki i Wigury 101, 02-089 Warsaw, Poland; Faculty of Chemistry, Laboratory of Basics of Analytical Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.GarstkaMaciejMFaculty of Biology, Department of Metabolic Regulation, Institute of Biochemistry, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland. Electronic address: garstka@biol.uw.edu.pl.engJournal Article20190122