Self-Assembled Protein Hybrid Nanofibrils for Photosynthetic Hydrogen Evolution

In artificial photosynthesis systems, synthetic diiron complexes are popular [FeFe]-hydrogenase mimics, which are attractive for the fabrication of photocatalyst-protein hybrid structures to amplify hydrogen (H2) generation capability. However, constructing a highly bionic and efficient catalytic hybrid system is a major challenge. Notably, we designed an ideal hybrid nanofibrils system that incorporates the crucial components: (1) a [FeFe]-H2ase mimic, which has a three-arm architecture (named triFeFe) for more interaction sites and higher catalytic activity and (2) uniform hybrid nanofibrils as the biological environment in which cysteine-catalyst coordination and the hydrogen-bonding network play a vital role in both catalyst binding and hydrogen evolution reaction activity. The assembled hybrid nanofibrils achieve efficient H2 generation with a turnover number of 2.3 x 103, outperforming previously reported diiron catalyst protein hybrid systems. Additionally, the hybrid nano fibrils work with photosynthetic thylakoids to produce H2, without extra photosensitizers or electron shuttle proteins, which advances the bioengineering of living systems for solar-driven biofuel production.