Crystal structure of the dimethylsulfide monooxygenase DmoA from Hyphomicrobium sulfonivorans.

DmoA is a monooxygenase which uses dioxygen (O2 ) and reduced flavin mononucleotide (FMNH2 ) to catalyze the oxidation of dimethylsulfide (DMS). Although it has been characterized, the structure of DmoA remains unknown. Here, the crystal structure of DmoA was determined to a resolution of 2.28 Å and was compared with those of its homologues LadA and BdsA. The results showed that their overall structures are similar: they all share a conserved TIM-barrel fold which is composed of eight α-helices and eight β-strands. In addition, they all have five additional insertions. Detailed comparison showed that the structures have notable differences despite their high sequence similarity. The substrate-binding pocket of DmoA is smaller compared with those of LadA and BdsA.