3 publications

3 publications

Aqueous Light Driven Hydrogen Production by a Ru–Ferredoxin–Co Biohybrid

Utschig, L.M.

Chem. Commun. 2015, 51, 10628-10631, 10.1039/c5cc03006d

Long-lived charge separation facilitates photocatalytic H2 production in a mini reaction center/catalyst complex.


Metal: Co
Ligand type: Oxime
Host protein: Ferredoxin (Fd)
Anchoring strategy: Dative
Optimization: ---
Reaction: H2 evolution
Max TON: 210
ee: ---
PDB: ---
Notes: Recalculated TON

Rational Design of a Miniature Photocatalytic CO2-Reducing Enzyme

Liu, X.; Tian, C.; Wang, J.

ACS Catal. 2021, 11, 5628-5635, 10.1021/acscatal.1c00287

Photosystem I (PSI) is a very large membrane protein complex (∼1000 kDa) harboring P700*, the strongest reductant known in biological systems, which is responsible for driving NAD(P)+ and ultimately for CO2 reduction. Although PSI is one of the most important components in the photosynthesis machinery, it has remained difficult to enhance PSI functions through genetic engineering due to its enormous complexity. Inspired by PSI’s ability to undergo multiple-step photo-induced electron hopping from P700* to iron–sulfur [Fe4S4] clusters, we designed a 33 kDa miniature photocatalytic CO2-reducing enzyme (mPCE) harboring a chromophore (BpC) and two [Fe4S4] clusters (FeA/FeB). Through reduction potential fine-tuning, we optimized the multiple-step electron hopping from BpC to FeA/FeB, culminating in a CO2/HCOOH conversion quantum efficiency of 1.43%. As mPCE can be overexpressed with a high yield in Escherichia coli cells without requiring synthetic cofactors, further development along this route may result in rapid photo-enzyme quantum yield improvement and functional expansion through an efficient directed evolution process.


Metal: Fe
Ligand type: Amino acid
Host protein: Ferredoxin (Fd)
Anchoring strategy: Dative
Optimization: Genetic
Reaction: CO2 reduction
Max TON: 35
ee: ---
PDB: ---
Notes: ---

Ru–protein–Co Biohybrids Designed for Solar Hydrogen Production: Understanding Electron Transfer Pathways Related to Photocatalytic Function

Utschig, L.M.

Chem. Sci. 2016, 7, 7068-7078, 10.1039/c6sc03121h

A series of Ru–protein–Co biohybrids have been prepared using the electron transfer proteins ferredoxin (Fd) and flavodoxin (Fld) as scaffolds for photocatalytic hydrogen production. The light-generated charge separation within these hybrids has been monitored by transient optical and electron paramagnetic resonance spectroscopies. Two distinct electron transfer pathways are observed. The Ru–Fd–Co biohybrid produces up to 650 turnovers of H2 utilizing an oxidative quenching mechanism for Ru(II)* and a sequential electron transfer pathway via the native [2Fe–2S] cluster to generate a Ru(III)–Fd–Co(I) charge separated state that lasts for ∼6 ms. In contrast, a direct electron transfer pathway occurs for the Ru–ApoFld–Co biohybrid, which lacks an internal electron relay, generating Ru(I)–ApoFld–Co(I) charge separated state that persists for ∼800 μs and produces 85 turnovers of H2 by a reductive quenching mechanism for Ru(II)*. This work demonstrates the utility of protein architectures for linking donor and catalytic function via direct or sequential electron transfer pathways to enable stabilized charge separation which facilitates photocatalysis for solar fuel production.


Metal: Co
Ligand type: Oxime
Host protein: Ferredoxin (Fd)
Anchoring strategy: Dative
Optimization: Chemical
Reaction: H2 evolution
Max TON: 650
ee: ---
PDB: ---
Notes: Recalculated TON