Functional characterization and molecular modeling of methylcatechol 2,3-dioxygenase from o-xylene-degrading Rhodococcus sp. strain DK17 |
| |
Authors: | Kim Dockyu Chae Jong-Chan Jang Jung Yeon Zylstra Gerben J Kim Young Min Kang Beom Sik Kim Eungbin |
| |
Affiliation: | Department of Biology, Institute of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea. |
| |
Abstract: | 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 beta10-beta11 loop play an essential role in characterizing the substrate specificity of AkbC. |
| |
Keywords: | Rhodococcus o-Xylene Catechol 2,3-dioxygenase Molecular model |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|