Modelling Photosynthesis with ZnII‐Protoporphyrin All‐DNA G‐Quadruplex/Aptamer Scaffolds

Abstract

AbstractAll‐DNA scaffolds act as templates for the organization of photosystem I model systems. A series of DNA templates composed of ZnII‐protoporphyrin IX (ZnIIPPIX)‐functionalized G‐quadruplex conjugated to the 3′‐ or 5′‐end of the tyrosinamide (TA) aptamer and ZnIIPPIX/G‐quadruplex linked to the 3′‐ and 5′‐ends of the TA aptamer through a four‐thymidine bridge. Effective photoinduced electron transfer (ET) from ZnIIPPIX/G‐quadruplex to bipyridinium‐functionalized tyrosinamide, TA‐MV2+, bound to the TA aptamer units is demonstrated. The effectiveness of the primary ET quenching of ZnIIPPIX/G‐quadruplex by TA‐MV2+ 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.