Direct visible light activation of a surface cysteine-engineered [NiFe]-hydrogenase by silver nanoclusters

Abstract

Engineering a cysteine close to the distal [4Fe–4S] cluster of a [NiFe]-hydrogenase creates a specific target for Ag nanoclusters, the resulting ‘hard-wired’ enzyme catalyzing rapid hydrogen evolution by visible light.

Mechanism and Application of the Catalytic Reaction of [NiFe] Hydrogenase: Recent Developments

“…Zhang et al. reported a systematic approach to re‐engineer O 2 ‐tolerant Ec [NiFe] H 2 ase for selective silver nanocluster (AgNC) attachment to the surface, leading to a ‘hard‐wired’ photoactive enzyme (Figure ) . A Cys222‐thiolate was engineered into Ec [NiFe] H 2 ase close to the distal [Fe 4 S 4 ] d 2+/+ cluster, at which electrons enter and leave the enzyme.…”

Light‐driven catalysis with engineered enzymes and biomimetic systems

“…For example, variants of oxygen-tolerant Ec-[NiFe]-Hyd-2 were engineered to enhance their interaction with silver nanoclusters (Fig. 9) [138]. Assisting this work was the structural characterization of the enzyme and the development of a system for high-yield expression [139].…”

“…3S1C-Hyd-2 has the greatest interaction with the nanoclusters as indicated via luminescence quenching, and the engineered cysteine residue ensures this interaction occurs near the distal [4Fe-4S] cluster. Adding metal oxide nanoparticles like TiO 2 that could bind to the silver nanoclusters greatly enhances the rate and total hydrogen production [138]. Notably, the variant with no cysteines (3S-Hyd-2) still underperforms compared with the other variants.…”

Recent Progress in Applications of Enzymatic Bioelectrocatalysis

“…Carbon nanomaterials, such as carbon nanotubes [57][58][59], carbon blacks [60], carbon cryogels [61,62], and MgO-templated carbons [43,63,64], have properties to physically adsorb a large amount of enzymes and mediators at hydrophobic sites and are generally used as platforms favorable for bioelectrocatalysis. On the other hand, nanoporous gold constructed by anodization [27,[65][66][67] or dealloying [68][69][70] and metallic nanoparticles of gold [57,[71][72][73][74][75][76][77][78], silver [79][80][81], platinum [29][30][31], titanium oxide (TiO 2 ) [80,81], iron oxide (Fe 2 O 3 ) [82,83], and indium tin oxide (ITO) [84] are also widely used. Compared to carbon nanomaterials, the pore and particle sizes of metallic nanomaterials can be easily controlled according to several manufacturing methods.…”

“…The electrons are then donated to substrates via enzymes and mediators, as shown in Figure 6. Photosensitizers such as TiO 2 [80,81,[160][161][162], PbS quantum dots [162], silver nanoclusters [80,81], and organic dyes [160,161] are incorporated in anodes of transparent electrode bases (ITO in general) with or without other catalysts. Particularly, in addition, the photosystem II (PSII) complex in the thylakoid membrane of cyanobacteria and higher plants is often used as a water-splitting anodic photo-bioelectrocatalyst [129,.…”