Molecular sequencing and analysis of soluble methane monooxygenase gene clusters from methanotroph Methylomonas sp. GYJ3

Summary A methanotroph Methylomonas sp. GYJ3 was isolated, whose sMMO genes and 16S rDNA were sequenced and analysed, demonstrating that the bacterium might be a type I methanotroph (γ-Proteobacteria) and was closer to Methylomonas sp. KSWIII/KSPIII. This result was consistent with the result previously determined by biochemistry and morphological taxonomy. Sequence comparison among six open reading frames and the deduced amino acid sequences of the sMMO genes from six strains revealed that the strain GYJ3 had highly conserved regions in MMOX with other strains, amounting to 78–99% homology at protein level and 71–97% homology at DNA level. Highly conserved sequences lay in two iron-binding regions. Furthermore, scanning electron microscopy of the strain GYJ3 showed rod shapes with a slightly bent configuration on the even surfaces and with plump bodies.