A bioinspired redox relay that mimics radical interactions of the Tyr-His pairs of photosystem II

作者：Megiatto Jackson D Jr^*; Mendez Hernandez Dalvin D; Tejeda Ferrari Marely E; Teillout Anne Lucie; Llansola Portoles Manuel J; Kodis Gerdenis; Poluektov Oleg G; Rajh Tijana; Mujica Vladimiro; Groy Thomas L; Gust Devens; Moore Thomas A; Moore Ana L

来源：Nature Chemistry, 2014, 6(5): 423-428.

DOI：10.1038/NCHEM.1862

In water-oxidizing photosynthetic organisms, light absorption generates a powerfully oxidizing chlorophyll complex (P680(center dot+)) in the photosystem II reaction centre. This is reduced via an electron transfer pathway from the manganese-containing water-oxidizing catalyst, which includes an electron transfer relay comprising a tyrosine (Tyr)-histidine (His) pair that features a hydrogen bond between a phenol group and an imidazole group. By rapidly reducing P680(center dot+), the relay is thought to mitigate recombination reactions, thereby ensuring a high quantum yield of water oxidation. Here, we show that an artificial reaction centre that features a benzimidazole-phenol model of the Tyr-His pair mimics both the short-internal hydrogen bond in photosystem II and, using electron paramagnetic resonance spectroscopy, the thermal relaxation that accompanies proton-coupled electron transfer. Although this artificial system is much less complex than the natural one, theory suggests that it captures the essential features that are important in the function of the relay.

• 出版日期2014-5