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.