S72: Biodegradation of s-triazines: Principles and applications

s-Triazine compounds comprise an important class of commercial chemicals. For example, they are used in agriculture as herbicides. A major s-triazine herbicide is atrazine, that is used principally in cornfields. The environmental fate of atrazine and other s-triazines is largely determined by their metabolism by soil bacteria. The metabolic pathway for atrazine degradation was elucidated. It proceeds via an initial dechlorination reaction catalyzed by atrazine chlorohydrolase. Data from molecular genetics, enzymology and kinetic isotope effect measurements suggested that this is the predominant biodegradative pathway in most environments. The structure and function of atrazine chlorohydrolase has been studied; the X-ray structure of one enzyme has been determined. Recombinant bacteria expressing atrazine chlorohydrolase are being used for atrazine remediation. Evolutionary aspects of the atrazine genes and enzymes will also be discussed.

Seffernick, J.L., E. Reynolds, A.A. Federov, E. Federov, S.C. Almo, M.J. Sadowsky, and L.P. Wackett (2010) X-ray structure and mutational analysis of the atrazine chlorohydrolase TrzN. J. Biol. Chem. 285:30606-30614.