Jiang Jian, Wang Hui, Gao Jing-si, Song Lei, Ning Da-liang
Institute of Environmental Biology, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
Huan Jing Ke Xue. 2008 Jun;29(6):1655-9.
Pseudomonas nitroreducens J5-1 is able to use monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene and 1,2,4-trichlorobenzene as sole carbon and energy sources, and it differs from those 1,2,4-trichlorobenzene degrading bacteria reported in substrate utilizing characters. PCR technique was used to amplify the genes of chlorobenzene dioxygenase and dehydrogenase of J5-1, and they were named as tcbA and tcbB, respectively. Homology analysis indicated that these genes and gene products were most closely related to those of Burkholderia sp. PS12. By alignment of the amino acid sequences of the a subunits of TcbAa (from J5-1) and TecA1 (from PS12), four amino acid residues from site 307 to site 310 were found to be different (I307L, M308T, I309V, Q310E), which probably retarded the preference for the substrate 1,2,4,5-tetrachlorobenzene. Furthermore, the phylogenetic analysis of the dioxygenase alpha subunits showed that TcbAa was belong to the toluene/diphenyl subfamily, and was most closely related to the poly-chlorinated benzene dioxygenase alpha subunit.
硝基还原假单胞菌J5-1能够利用一氯苯、1,2-二氯苯、1,3-二氯苯和1,2,4-三氯苯作为唯一碳源和能源，且在底物利用特性方面与已报道的1,2,4-三氯苯降解菌不同。采用PCR技术扩增J5-1的氯苯双加氧酶基因和脱氢酶基因，分别命名为tcbA和tcbB。同源性分析表明，这些基因及其产物与伯克霍尔德菌属PS12的基因和产物关系最为密切。通过比对TcbAa（来自J5-1）和TecA1（来自PS12）的α亚基氨基酸序列，发现第307位至第310位有四个氨基酸残基不同（I307L、M308T、I309V、Q310E），这可能影响了对底物1,2,4,5-四氯苯的偏好。此外，双加氧酶α亚基的系统发育分析表明，TcbAa属于甲苯/二苯亚家族，与多氯苯双加氧酶α亚基关系最为密切。
