title: Ancient Evolution and Recent Evolution Converge for the Biodegradation of Cyanuric Acid and Related Triazines.
abstract: Cyanuric acid was likely present on prebiotic Earth, may have been a component of early genetic materials, and is synthesized industrially today on a scale of more than one hundred million pounds per year in the United States. In light of this, it is not surprising that some bacteria and fungi have a metabolic pathway that sequentially hydrolyzes cyanuric acid and its metabolites to release the nitrogen atoms as ammonia to support growth. The initial reaction that opens the s-triazine ring is catalyzed by the unusual enzyme cyanuric acid hydrolase. This enzyme is in a rare protein family that consists of only cyanuric acid hydrolase (CAH) and barbiturase, with barbiturase participating in pyrimidine catabolism by some actinobacterial species. The X-ray structures of two cyanuric acid hydrolase proteins show that this family has a unique protein fold. Phylogenetic, bioinformatic, enzymological, and genetic studies are consistent with the idea that CAH has an ancient protein fold that was rare in microbial populations but is currently becoming more widespread in microbial populations in the wake of anthropogenic synthesis of cyanuric acid and other s-triazine compounds that are metabolized via a cyanuric acid intermediate. The need for the removal of cyanuric acid from swimming pools and spas, where it is used as a disinfectant stabilizer, can potentially be met using an enzyme filtration system. A stable thermophilic cyanuric acid hydrolase from Moorella thermoacetica is being tested for this purpose.
authors.affiliation: Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, St. Paul, Minnesota, USA.|BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, USA.|Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Seffernick
authors.affiliation: Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, St. Paul, Minnesota, USA wacke003@umn.edu.|BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, USA.|Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Wackett
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics; D019143:Evolution, Molecular; D005658:Fungi / Q000201:enzymology* / Q000235:genetics; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D014227:Triazines / Q000378:metabolism*
chemical_list: D014227:Triazines; D000581:Amidohydrolases; C067141:cyanuric acid amidohydrolase