Analysis of photosystem II electron transfer with natural PsbA-variants by redox polymer/protein biophotoelectrochemistry

作者：Hartmann V; Ruff A; Schuhmann W; Roegner M; Nowaczyk M M^*

来源：Photosynthetica, 2018, 56(1): 229-235.

DOI：10.1007/s11099-018-0775-y

• biophotovoltaics
• cyanobacteria
• D1-protein
• hydrogel

Redox polymer/protein biophotoelectrochemistry was used to analyse forward electron transfer of isolated PSII complexes with natural PsbA-variants. PsbA1- or PsbA3-PSII was embedded in a redox hydrogel that allows diffusion-free electron transfer to the electrode surface and thus measurement of an immediate photocurrent response. The initial photocurrent density of the electrode is up to similar to 2-fold higher with PsbA1-PSII under all tested light conditions, the most prominent under high-light [2,300 mu mol(photon) m(-2) s(-1)] illumination with 5 mu A cm(-2) for PsbA3-PSII and 9.5 mu A cm(-2) for PsbA1-PSII. This indicates more efficient electron transfer in low-light-adapted PsbA1-PSII. In contrast, the photocurrent decays faster in PsbA1-PSII under all tested light conditions, which suggests increased stability of high-light-adapted PsbA3-PSII. These results confirm and extend previous observations that PsbA3-PSII has increased P680(+center dot)/Q(A)(-center dot) charge recombination and thus less efficient photon-to-charge conversion, whereas PsbA1-PSII is optimised for efficient electron transfer with limited stability.

• 出版日期2018-3