Protein film photoelectrochemistry of the water oxidation enzyme photosystem II

Abstract

Photosynthesis is responsible for the sunlight-powered conversion of carbon dioxide and water into chemical energy in the form of carbohydrates and the release of O2 as a by-product. Although many proteins are involved in photosynthesis, the fascinating machinery of Photosystem II (PSII) is at the heart of this process. This tutorial review describes an emerging technique named protein film photoelectrochemistry (PF-PEC), which allows for the light-dependent activity of PSII adsorbed onto an electrode surface to be studied. The technique is straightforward to use, does not require highly specialised and/or expensive equipment, is highly selective for the active fractions of the adsorbed enzyme, and requires a small amount of enzyme sample. The use of PF-PEC to study PSII can yield insights into its activity, stability, quantum yields, redox behaviour, and interfacial electron transfer pathways. It can also be used in PSII inhibition studies and chemical screening, which may prove useful in the development of biosensors. PSII PF-PEC cells also serve as proof-of-principle solar water oxidation systems; here, a comparison is made against PSII-inspired synthetic photocatalysts and materials for artificial photosynthesis.

Solar-driven proton and carbon dioxide reduction to fuels — lessons from metalloenzymes

“…Although PFE studies of PSII are limited compared with H2ase and CODH, the enzyme displays photoelectrocatalysis when interfaced with different nanomaterials [26] the light-harvesting and catalytic components being inseparable parts of the same super-molecule. Recent reports include O 2 evolution by His-tagged PSII immobilised on Au-nanoparticles [27], using mesoporous indium-tin oxide electrodes for direct and mediated electron transfer (ET) [28], covalent anchoring [29], and incorporation into redoxactive polymers [30][31][32].…”

Assembly of CdTe Quantum Dots and Photosystem II Multilayer Films with Enhanced Photocurrent

“…In order to evaluate the photoelectrical performance of the above biohybrid electrodes, photochronoamperometric measurements were carried out in the presence of [Fe(CN) 6 ] 3/4 as a redox mediator. The photocurrent production of the PSII-PAH/CdTe biohybrid photoanodes under UV light (λ＝365 nm) irradiation with different amount of PSII was shown in Figure 4b.…”

“…CaCl 2 and 1.5 mmol•L 1 K 4 Fe(CN) 6 was used as the electrolyte. Before irradiation, the solution was bubbled with N 2 for at least 1 h to eliminate dissolved O 2 and the whole experimental process was conducted under N 2 protection.…”

“…[2,3] Meanwhile, immense studies on native photosystems based solar energy conversion systems have been carried out because of their low-cost and fine availability. [4][5][6][7] Photosystem II (PSII) is a transmembrane protein that resides in thylakoid membranes of higher plants, algae and cyanobacteria, which is the only protein known that can drive solar water splitting reaction at room temperature and atmosphere pressure. The redox potential of the oxidized primary electron donor of PSII is about ＋ 1.25 V vs. normal hydrogen electrode (NHE), which is high enough to oxidize water in a pH neutral aqueous solution.…”

Enzymes as Exploratory Catalysts in Artificial Photosynthesis

“…Copyright (2013) American Chemical Society [ 29 ] interaction with self-assembled monolayers on the ITO surface improved the interfacial electronic communication between ITO and PSII and substantially enhanced the turnover frequencies for light-driven oxygen evolution [ 31 ]. Protein fi lm photoelectrochemistry [ 32 ] is an emerging technique that may further light on the reactivity of nature's superb oxygen evolution system.…”