Wang Y, Rawlings M, Gibson D T, Labbé D, Bergeron H, Brousseau R, Lau P C
Biotechnology Research Institute, National Research Council of Canada, Montréal, Québec.
Mol Gen Genet. 1995 Mar 10;246(5):570-9. doi: 10.1007/BF00298963.
A 3 kb DNA region upstream of the toluene degradation (tod) genes, todFC1C2BADEGIH, in Pseudomonas putida F1 (PpF1) was sequenced. Two divergently arranged open reading frames, todR and todX, were identified. A toluene-inducible promoter was localized in front of todX, and the transcription start point was mapped. This promoter is probably responsible for the expression of all tod structural genes. TodX was found to be a membrane protein. Its predicted amino acid sequence (453 residues; M(r) 48,265) exhibits considerable similarity with the FadL protein of Escherichia coli, an outer membrane protein required for binding and transport of long-chain fatty acids. An apparent function of TodX is likely to be involved in facilitating the delivery of exogenous toluene inside the PpF1 cells. The sequence of TodR (100 residues) exhibits extensive homology with the DNA-binding domain of transcriptional activators of the LysR family, but todR was found to have a negligible role in tod gene regulation.
对恶臭假单胞菌F1（PpF1）中甲苯降解（tod）基因todFC1C2BADEGIH上游3 kb的DNA区域进行了测序。鉴定出两个反向排列的开放阅读框，即todR和todX。一个甲苯诱导型启动子定位于todX的前方，并确定了转录起始点。该启动子可能负责所有tod结构基因的表达。发现TodX是一种膜蛋白。其预测的氨基酸序列（453个残基；M(r) 48,265）与大肠杆菌的FadL蛋白具有相当的相似性，FadL蛋白是一种外膜蛋白，是长链脂肪酸结合和运输所必需的。TodX的一个明显功能可能是促进外源甲苯在PpF1细胞内的传递。TodR（100个残基）的序列与LysR家族转录激活因子的DNA结合结构域具有广泛的同源性，但发现todR在tod基因调控中作用可忽略不计。
