Rhodococcus sp. strain DK17 is known to metabolize o-xylene and toluene through the intermediates 3,4-dimethylcatechol and 3- and 4-methylcatechol, respectively, which are further cleaved by a common catechol 2,3-dioxygenase. A putative gene encoding this enzyme (akbC) was amplified by PCR, cloned, and expressed in Escherichia coli. Assessment of the enzyme activity expressed in E. coli combined with sequence analysis of a mutant gene demonstrated that the akbC gene encodes the bona fide catechol 2,3-dioxygenase (AkbC) for metabolism of o-xylene and alkylbenzenes such as toluene and ethylbenzene. Analysis of the deduced amino acid sequence indicates that AkbC consists of a new catechol 2,3-dioxygenase class specific for methyl-substituted catechols. A computer-aided molecular modeling studies suggest that amino acid residues (particularly Phe177) in the β10-β11 loop play an essential role in characterizing the substrate specificity of AkbC.
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 2005 Jan 28|
Bibliographical noteFunding Information:
This work was substantially supported by a grant from the Ministry of Science and Technology, Republic of Korea, to E.K. (MG02-0301-005-1-0-0) through the 21C Frontier Microbial Genomics and Application Center Program. Scientific exchange visits were supported in part by a grant from KOSEF through the Advanced Environmental Biotechnology Research Center at POSTECH. G.J.Z. acknowledges the support of NSF through Grants MCB-0078465 and CHE-9810248.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology