Black R A, Hobson A C, Adler J
J Bacteriol. 1983 Mar;153(3):1187-95. doi: 10.1128/jb.153.3.1187-1195.1983.
We report that in Escherichia coli, chemotaxis to sugars transported by the phosphotransferase system is mediated by adenylate cyclase, the nucleotide cyclase linked to the phosphotransferase system. We conclude that adenylate cyclase is required in this chemotaxis pathway because mutations in the cyclase gene (cya) eliminate or impair the response to phosphotransferase system sugars, even though other components of the phosphotransferase system known to be required for the detection of these sugars are relatively unaffected by such mutations. Moreover, merely supplying the mutant bacteria with the products of this enzyme, cyclic AMP and cyclic GMP, does not restore the chemotactic response. Because a residual chemotactic response is observed in certain strains with residual cyclic GMP synthesis but no cyclic AMP synthesis, it appears that the guanylate cyclase activity rather than the adenylate cyclase activity of the enzyme may be required for chemotaxis to sugars transported by the phosphotransferase system. Mutations in the cyclic nucleotide phosphodiesterase gene, which increase the level of both cyclic AMP and cyclic GMP, also reduce chemotaxis to these sugars. Therefore, it appears that control of the level of a cyclic nucleotide is critical for the chemotactic response to phosphotransferase system sugars.
我们报告称，在大肠杆菌中，对由磷酸转移酶系统转运的糖类的趋化作用是由腺苷酸环化酶介导的，腺苷酸环化酶是与磷酸转移酶系统相连的核苷酸环化酶。我们得出结论，在这条趋化途径中需要腺苷酸环化酶，因为环化酶基因（cya）的突变会消除或损害对磷酸转移酶系统糖类的反应，尽管已知检测这些糖类所需的磷酸转移酶系统的其他组分相对不受此类突变的影响。此外，仅向突变细菌提供该酶的产物，即环腺苷酸（cAMP）和环鸟苷酸（cGMP），并不能恢复趋化反应。因为在某些具有残余环鸟苷酸合成但无环腺苷酸合成的菌株中观察到残余的趋化反应，所以看来对于由磷酸转移酶系统转运的糖类的趋化作用，可能需要该酶的鸟苷酸环化酶活性而非腺苷酸环化酶活性。环核苷酸磷酸二酯酶基因的突变会增加环腺苷酸和环鸟苷酸的水平，这也会降低对这些糖类的趋化作用。因此，看来环核苷酸水平的控制对于对磷酸转移酶系统糖类的趋化反应至关重要。
