Hydroxylation of the non-growth substrate biphenyl by recombinant o-xylene dioxygenases from Rhodococcus sp. strain DK17 was studied through bioconversion experiments. The metabolites from the biphenyl hydroxylation by each enzyme were identified and quantified by gas chromatography-mass spectrometry. The L266F mutant enzyme produced much more 2-hydroxybiphenyl (2.43 vs. 0.1 μg/L) and 3-hydroxybiphenyl (1.97 vs. 0.03 μg/L) than the wild-type. Site-directed mutagenesis combined with structural and functional analyses indicated that hydrophobic interactions and shielding effects against water are important factors in the hydroxylation of biphenyl by the o-xylene dioxygenase. The residue at position 266 plays a key role in coordinating the reaction.
Bibliographical noteFunding Information:
This work was supported by a grant to the 21C Frontier Microbial Genomics and Applications Center Program and by grant 2009-0079296 to the Basic Science Research Program through the National Research Foundation of Korea . Both are funded by the Ministry of Education, Science, and Technology of the Republic of Korea . DK is supported by the Korea Polar Research Institute under projects PE10050 and PE11060. GJZ acknowledges the support of NIEHS grant P42-ES004911 under the Superfund Basic Science Program. MY is a recipient of the Brain Korea 21 scholarship.
All Science Journal Classification (ASJC) codes
- Molecular Biology