Diiron Dithiolate Complex Induced Helical Structure of Histone and Application in Photochemical Hydrogen Generation

Very-lysine-rich calf thymus histone proteins form disordered structure and hydrophobic interaction-driven aggregates in weakly acidic solution. We reported that the conjugation of diiron dithiolate complex to the lysine residues induced formation of helical conformation and condensed nanoassemblies with a high loading capacity up to 18.7 wt %. The incorporated diiron dithiolate complex showed photocatalytic activity for hydrogen evolution in aqueous solutions, with a turnover number (based on [FeFe] catalyst moiety) up to 359 that was more than 6 times that of the free catalyst. The increase of helical conformation in proteins was well correlated to the increasing enhancement of photocatalytic activity. We demonstrated that the [FeFe]-hydrogenase-mimic biohybrid system based on the photocatalyst-induced protein conformational conversion and reassembly is efficient for hydrogen generation regardless of the relatively large size.