Identification of a ubiG-like gene involved in ubiquinone biosynthesis from Chlamydophila pneumoniae AR39

AIMS: To investigate if one hypothetical protein from Chlamydophila pneumoniae AR39 exerts UbiG-like function by complementary experiments. METHODS AND RESULTS: Proteins UbiG have a signature S-adenosylmethionine-binding motif compared with other methyltransferases. Probing with the conserved motif, one hypothetical protein from C. pneumoniae AR39 was proposed to be a UbiG-like protein. The protein encoding the gene was used to swap its counterpart in Escherichia coli, and its expression in resultant strain DYCG was confirmed by RT-PCR. Strain DYCG grew on succinate as a carbon source, and rescued ubiquinone content in vivo, while the ubiG deletion strain DYK did not. CONCLUSIONS: Results indicate that the putative protein from C. pneumoniae exerts a UbiG-like function involved in ubiquinone biosynthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of the ubiG-like gene will facilitate research on ubiquinone biosynthesis and aerobic respiration in the genus Chlamydophila owing to the important function of ubiquinone in vivo.