Genetic rearrangement strategy for optimizing the dibenzothiophene biodesulfurization pathway in Rhodococcus erythropolis.
Dibenzothiophene (DBT) and its derivatives can be microbially desulfurized by enzymes DszC, DszA, and DszB, which are encoded by the operon dszABC and contribute to the conversion in tandem. We investigated the expression characteristics of the dsz operon. Our results revealed that the levels of transcription and translation of dszA, dszB, and dszC decreased according to the positions of the genes in the dsz operon. Furthermore, the translation of dszB was repressed by an overlapping structure in the dsz operon. In order to get better and steady expression of the Dsz enzymes and optimize the metabolic flux of DBT, we rearranged the dsz operon according to the catalytic capabilities of the Dsz enzymes and expressed the rearranged dsz operon, dszBCA, in Rhodococcus erythropolis. After rearrangement, the ratio of dszA, dszB, and dszC mRNAs in the cells was changed, from 11:3.3:1 to 1:16:5. Western blot analysis revealed that the levels of expression of dszB and dszC had been enhanced but that the expression of dszA had decreased. The desulfurization activity of resting cells prepared from R. erythropolis DRB, which carried the rearranged dsz operon, was about 12-fold higher than that of resting cells of R. erythropolis DRA, which carried the original operon in a similarly constructed vector.
Li
Guo-qiang
GQ
College of Environment Sciences and Engineering, Nankai University, Tianjin 300071, China.
Li
Shan-shan
SS
Zhang
Ming-lu
ML
Wang
Jun
J
Zhu
Lin
L
Liang
Feng-lai
FL
Liu
Ru-lin
RL
Ma
Ting
T
D015153:Blotting, Western; D018274:Electroporation; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D005818:Genetic Engineering; D009876:Operon / Q000235:genetics; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D012240:Rhodococcus / Q000235:genetics / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*; D013876:Thiophenes / Q000378:metabolism*
D013876:Thiophenes; D013455:Sulfur; D010105:Oxygenases; C421210:dibenzothiophene sulfone monooxygenase; C016366:dibenzothiophene