Modelling Photosynthesis with Zn -Protoporphyrin All-DNA G-Quadruplex/Aptamer Scaffolds.

All-DNA scaffolds act as templates for the organization of photosystem I model systems. A series of DNA templates composed of Zn -protoporphyrin IX (Zn PPIX)-functionalized G-quadruplex conjugated to the 3'- or 5'-end of the tyrosinamide (TA) aptamer and Zn PPIX/G-quadruplex linked to the 3'- and 5'-ends of the TA aptamer through a four-thymidine bridge. Effective photoinduced electron transfer (ET) from Zn PPIX/G-quadruplex to bipyridinium-functionalized tyrosinamide, TA-MV , bound to the TA aptamer units is demonstrated. The effectiveness of the primary ET quenching of Zn PPIX/G-quadruplex by TA-MV controls the efficiency of the generation of TA-MV . The photosystem-controlled formation of TA-MV by the different photosystems dictates the secondary activation of the ET cascade corresponding to the ferredoxin-NADP reductase (FNR)-catalysed reduction of NADP to NADPH by TA-MV , and the sequestered alcohol dehydrogenase catalysed reduction of acetophenone to 1-phenylethanol by NADPH.