OYE Flavoprotein Reductases Initiate the Condensation of TNT-Derived Intermediates to Secondary Diarylamines and Nitrite Rolf-Michael Wittich Alí Haïdour Pieter Van Dillewijn Juan-Luis Ramos 10.1021/es071449w.s001 https://acs.figshare.com/articles/journal_contribution/OYE_Flavoprotein_Reductases_Initiate_the_Condensation_of_TNT_Derived_Intermediates_to_Secondary_Diarylamines_and_Nitrite/2960056 Polynitroaromatic explosives such as 2,4,6-trinitrophenol (picric acid) and 2,4,6-trinitrotoluene (TNT) are toxic and recalcitrant environmental pollutants. They persist in the environment due to the highly inactivated π system of their aromatic rings, which are inaccessible to dioxygenases that normally initiate the bacterial aerobic catabolism of (nitro-) aromatic compounds. Aside from reductive transformation of nitro side groups to hydroxylamines, trinitroarenes are prone to aromatic ring reductions by some flavin reductases to yield Meisenheimer mono and dihydride complexes. Here we show that the simultaneous accumulation of Meisenheimer complexes and aromatic hydroxylamines derived from TNT gives rise to the condensation of both types of reactive intermediates to secondary diarylamines and nitrite as the end-products of this environmentally relevant reaction sequence. As a consequence, overall mass balances of aerobic biotransformations of TNT become possible for the first time. In our study, the process of TNT activation was enzymatically initiated by the xenobiotic reductase B (XenB)-like flavin reductase of Pseudomonas putida JLR11 and then completed chemically by autodimerization. The structures of the formed end products were unequivocally elucidated by NMR. 2008-02-01 00:00:00 hydroxylamine OYE Flavoprotein Reductases Initiate reaction sequence picric acid dihydride complexes NitritePolynitroaromatic explosives reactive intermediates Pseudomonas putida JLR 11 ring reductions π system xenobiotic reductase B flavin reductases NMR nitro side groups reductive transformation end products Meisenheimer complexes Secondary Diarylamines TNT activation mass balances