Newly Discovered PQQ-Dependent Enzyme Family in Eukaryotes

What is it about?

Researchers discovered a novel PQQ-dependent sugar oxidoreductase in a mushroom, Coprinopsis cinerea. The enzyme, named CcSDH, was found to be PQQ-dependent and exhibited catalytic activity toward various sugars. BLAST search identified several genes, including homologous genes to the cytochrome domain of CcSDH, in the C. cinerea genome. The recombinant protein was expressed in Pichia pastoris and purified through column chromatography. CcSDH showed strong binding activity to PQQ, and the binding constant was estimated by ITC. The three-dimensional structure of CcSDH was predicted to have a six-bladed quinoprotein structure, similar to other known prokaryotic sugar dehydrogenases. The discovery of CcSDH expands our understanding of PQQ-dependent enzymes and their diversity in various organisms.

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Why is it important?

This research is important because it identifies a novel PQQ-dependent sugar oxidoreductase in a mushroom, extending our understanding of PQQ-dependent enzymes beyond prokaryotes to eukaryotes. This discovery enables further exploration of the role and significance of PQQ in sugar metabolism and other biological processes. It also contributes to the understanding of the evolutionary relationships between different organisms and the distribution of PQQ-dependent enzymes across different domains of life. Key Takeaways: 1. A novel PQQ-dependent sugar oxidoreductase was discovered in a mushroom, expanding our knowledge of PQQ-dependent enzymes to eukaryotes. 2. The protein has a signal peptide for extracellular secretion and a domain for adsorption on cellulose, in addition to the PQQ-dependent sugar dehydrogenase and cytochrome domains. 3. The enzyme shows PQQ-dependent activity and strongly binds PQQ. 4. The research uncovered genes encoding homologous proteins in bacteria, archaea, amoebozoa, and fungi, suggesting a widely distributed, new family of quinoproteins in prokaryotes and eukaryotes.