Competing charge transfer pathways at the photosystem II-electrode interface

Jenny Z. Zhang, Katarzyna P. Sokol, Nicholas Paul, Elisabet Romero, Rienk Van Grondelle, Erwin Reisner*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The integration of the water-oxidation enzyme photosystem II (PSII) into electrodes allows the electrons extracted from water oxidation to be harnessed for enzyme characterization and to drive novel endergonic reactions. However, PSII continues to underperform in integrated photoelectrochemical systems despite extensive optimization efforts. Here we carried out protein-film photoelectrochemistry using spinach and Thermosynechococcus elongatus PSII, and we identified a competing charge transfer pathway at the enzyme-electrode interface that short-circuits the known water-oxidation pathway. This undesirable pathway occurs as a result of photo-induced O2 reduction occurring at the chlorophyll pigments and is promoted by the embedment of PSII in an electron-conducting fullerene matrix, a common strategy for enzyme immobilization. Anaerobicity helps to recover the PSII photoresponse and unmasks the onset potentials relating to the QA/QB charge transfer process. These findings impart a fuller understanding of the charge transfer pathways within PSII and at photosystem-electrode interfaces, which will lead to more rational design of pigment-containing photoelectrodes in general.

Original languageEnglish
Pages (from-to)1046-1052
Number of pages7
JournalNature Chemical Biology
Volume12
Issue number12
DOIs
Publication statusPublished - 1 Dec 2016

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