A Semisynthetic Peptide−Metalloporphyrin Responsive Matrix for Artificial Photosynthesis

Abstract

The CsmA protein from the baseplate of the Chlorobaculum tepidum is proposed as an attractive motif for the engineering of semisynthetic materials for artificial photosynthesis. We perform self-assembly of zinc protoporphyrin IX (ZnPP) with a truncated CsmA (tCsmA) amphipathic peptide scaffold for the bottom-up construction of a semisynthetic matrix for energy transfer. The resulting self-assembly shows an extended periodic structure with 72 helical symmetry. The complex is able to maintain a good photostability for at least 30 min when the concentration is more than 20 μM, and almost 100 % harvested energy can be transferred to the acceptor cation radical methyl viologen (MV+). The excitation-energy transfer rate of the complex was increased from the ns−1 scale to the ps−1 scale that is comparable to natural light-harvesting antenna systems. It contributes to converging evidence that chiral responsive matrix assemblies can be developed for efficient light energy harvesting in artificial photosynthesis.