Kleene S J, Hobson A C, Adler J
Proc Natl Acad Sci U S A. 1979 Dec;76(12):6309-13. doi: 10.1073/pnas.76.12.6309.
During bacterial chemotaxis, attractants and repellents alter the methylation levels of the methyl-accepting chemotaxis proteins (MCPs). These methylation levels represent a balance between two enzymatic processes: methylation and demethylation. In vivo experiments previously have shown that chemoeffectors influence the demethylation process; effects on the methylation system have not been reported. Here we show that in a cell-free extract of Escherichia coli both methylation and demethylation of the MCPs are affected by attractants and repellents. Attractants enhance methylation and inhibit demethylation. Repellents inhibit methylation and stimulate demethylation. The cell-free system provides an opportunity for further study of the mechanisms by which attractants and repellents influence the levels of methylation of the MCPs.
在细菌趋化作用过程中，引诱剂和驱避剂会改变甲基化趋化蛋白（MCPs）的甲基化水平。这些甲基化水平代表了两个酶促过程之间的平衡：甲基化和去甲基化。此前的体内实验表明，化学效应物会影响去甲基化过程；对甲基化系统的影响尚未见报道。在此我们表明，在大肠杆菌的无细胞提取物中，MCPs的甲基化和去甲基化均受引诱剂和驱避剂影响。引诱剂增强甲基化并抑制去甲基化。驱避剂抑制甲基化并刺激去甲基化。该无细胞系统为进一步研究引诱剂和驱避剂影响MCPs甲基化水平的机制提供了机会。
