Photosensitizers, which harness light energy to upgrade weak reductants to strong reductants, are pivotal components of the natural and artificial photosynthesis machineries. However, it has proved difficult to enhance and expand their functions through genetic engineering. Here we report a genetically encoded photosensitizer protein (PSP), which facilitates the rational design of miniature photocatalytic CO2-reducing enzymes. Visible light drives PSP efficiently into a long-lived triplet excited state (PSP*), which reacts rapidly with reduced nicotinamide adenine dinucleotide to generate a super-reducing radical (PSPdot), which is strong enough to reduce many CO2-reducing catalysts. Genetic engineering enabled the site-specific attachment of a nickel-terpyridine complex and the modular optimization of the photochemical properties of PSP, the chromophore/catalytic center distance and the catalytic center microenvironment, which culminated in a miniature photocatalytic CO2-reducing enzyme that has a CO2/CO conversion quantum efficiency of 2.6%. Recently, we have made significant progress in the further optimization of mPCE, and the conversion on non-photosynthetic organism (such as E coli.) to artificial photosynthetic cells, which has dramatically enhanced the ability of these biological cell factory to synthesize high-value chemicals and materials.

Genetically encoded photosensitizer protein facilitates the rational design of a miniature photocatalytic CO2 reducing enzyme

2019 Fall National Meeting

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