Scheler A, Hillen W
Lehrstuhl für Mikrobiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.
Mol Microbiol. 1994 Aug;13(3):505-12. doi: 10.1111/j.1365-2958.1994.tb00445.x.
Xylose utilization in Bacillus licheniformis is inducible by xylose. We establish here that the Xyl repressor recognizes and binds an xyl operator sequence located 12 nucleotides downstream from the transcription start site of the xyl operon. DNA-retardation experiments employing xyl regulatory DNA and soluble protein extracts indicate complex formation in the presence of Xyl repressor. Two repressor-operator complexes are distinguished by different gel mobilities. They yield the same in situ copper-phenanthroline footprint. This result suggests that a single xyl operator may be bound by different oligomers of Xyl repressor. Methylation and hydroxyl radical cleavage protection of the xyl operator by Xyl repressor binding and ethylation interference of Xyl repressor binding to the xyl operator reveals symmetrical interaction of the repressor with two half sites of the operator, which show palindromic symmetry and are located on the same side of the B-form DNA structure.
地衣芽孢杆菌中木糖的利用可被木糖诱导。我们在此证实，木糖阻遏物识别并结合位于木糖操纵子转录起始位点下游12个核苷酸处的木糖操纵序列。使用木糖调控DNA和可溶性蛋白提取物进行的DNA阻滞实验表明，在木糖阻遏物存在的情况下会形成复合物。两种阻遏物 - 操纵子复合物通过不同的凝胶迁移率得以区分。它们产生相同的原位铜 - 菲咯啉足迹。这一结果表明，单个木糖操纵子可能被木糖阻遏物的不同寡聚体所结合。木糖阻遏物结合对木糖操纵子的甲基化和羟基自由基切割保护以及木糖阻遏物与木糖操纵子结合的乙基化干扰揭示了阻遏物与操纵子的两个半位点的对称相互作用，这两个半位点呈现回文对称，且位于B型DNA结构的同一侧。
