Replica of a fishy enzyme: structure–function analogue of trimethylamine-N-oxide reductase

Abstract

Three new complexes, [Mo^IVO(mnt)(SS)]^2- (SS = dimethylethylenedicarboxylate (DMED), toluenedithiolate (tdt), benzenedithiolate (bdt); mnt = maleonitriledithiolate), each possessing two different dithiolene ligands, are synthesized as model of trimethylamine-N-oxide reductase. The asymmetric dithiolene ligands present in these complexes simulate the two different (P and Q) pterin coordinations in the family of DMSO reductase. These complexes reduce trimethylamine-N-oxide ((CH₃)₃N⁺–O^– or TMANO), the biological substrate of trimethylamine-N-oxide reductase, to trimethylamine ((CH₃)₃N), responsible for the fishy smell of dead aquatic animals. The reaction kinetics of trimethylamine-N-oxide reduction by these complexes follow the Michaelis–Menten saturation kinetics. These experimental findings have been rationalized by DFT, TD-DFT level of calculations.