Discovery of Novel Selenite Reductase Enzymes for Selenium Nanoparticle Formation

Researchers from the Guangdong Technion Israel Institute of Technology have made a breakthrough discovery in the field of nanotechnology, identifying and characterizing a novel enzyme, CaSrpA, that can efficiently reduce selenite to selenium nanoparticles. This finding has significant implications for the development of sustainable and environmentally friendly methods for selenium recovery and utilization.

Key Takeaways:

• The research identified 40 putative selenite reductases from selenium-rich regions, with CaSrpA being the most active enzyme in reducing selenite to selenium nanoparticles.
• CaSrpA possesses a high activity of 18.85 mM/min/g in reducing selenite to selenium nanoparticles, making it a potential biocatalyst for selenium recovery.
• The enzyme CaSrpA is a member of the short-chain dehydrogenase/reductase (SDR) family, which is widely distributed across various oxidoreductase families.
• Phylogenetic analysis showed that CaSrpA was clustered in the clade of SDR enzymes, sharing a high sequence similarity with other SDR enzymes.
• Site-directed mutagenesis revealed that mutant M206A enhanced catalytic efficiency towards selenite by 2.4-fold and S-1-phenylethanol by 5.4-fold via a lid-opening mechanism.
• Molecular dynamics simulation elucidated that the mutant M206A used a lid-opening mechanism to accommodate more substrate and co-factor for catalysis via altering the conformation of the a7-a8 loop.

Statistics:

• 40 putative selenite reductases were identified from selenium-rich regions based on catalytic domain homology and transcriptional upregulation.
• CaSrpA showed a high activity of 18.85 mM/min/g in reducing selenite to selenium nanoparticles.
• Tyrusull Murong', a putative selenite reductase, showed a high activity of 15.4 mM/min/mg in oxidizing S-1-phenylethanol to phenylacetone.
• The mutant M206A enhanced catalytic efficiency towards selenite by 2.4-fold and S-1-phenylethanol by 5.4-fold via a lid-opening mechanism.

Sources:

• Identification and functional characterization of a novel CaSrpA enzyme for selenite reduction and selenium nanoparticle formation. Journal of Hazardous Materials, 2025;494:138486.
• Guangdong Technion Israel Institute of Technology.