Tribhuwan R C, Johnson M S, Taylor B L
J Bacteriol. 1986 Nov;168(2):624-30. doi: 10.1128/jb.168.2.624-630.1986.
Defects in phosphotransferase chemotaxis in cya and cpd mutants previously cited as evidence of a cyclic GMP or cyclic AMP intermediate in signal transduction were not reproduced in a study of chemotaxis in Escherichia coli and Salmonella typhimurium. In cya mutants, which lack adenylate cyclase, the addition of cyclic AMP was required for synthesis of proteins that were necessary for phosphotransferase transport and chemotaxis. However, the induced cells retained normal phosphotransferase chemotaxis after cyclic AMP was removed. Phosphotransferase chemotaxis was normal in a cpd mutant of S. typhimurium that has elevated levels of cyclic GMP and cyclic AMP. S. typhimurium crr mutants are deficient in enzyme III glucose, which is a component of the glucose transport system, and a regulator of adenylate cyclase. After preincubation with cyclic AMP, the crr mutants were deficient in enzyme II glucose-mediated transport and chemotaxis, but other chemotactic responses were normal. It is concluded that cyclic GMP does not determine the frequency of tumbling and is probably not a component of the transduction pathway. The only known role of cyclic AMP is in the synthesis of some proteins that are subject to catabolite repression.
先前被引为信号转导中存在环鸟苷酸或环腺苷酸中间体证据的环化酶（cya）和环化磷酸二酯酶（cpd）突变体中磷酸转移酶趋化性的缺陷，在一项关于大肠杆菌和鼠伤寒沙门氏菌趋化性的研究中未得到重现。在缺乏腺苷酸环化酶的cya突变体中，磷酸转移酶转运和趋化性所需蛋白质的合成需要添加环腺苷酸。然而，在去除环腺苷酸后，诱导细胞仍保留正常的磷酸转移酶趋化性。鼠伤寒沙门氏菌cpd突变体中的磷酸转移酶趋化性正常，该突变体中环鸟苷酸和环腺苷酸水平升高。鼠伤寒沙门氏菌crr突变体缺乏酶III葡萄糖，它是葡萄糖转运系统的一个组成部分，也是腺苷酸环化酶的调节剂。在用环腺苷酸预孵育后，crr突变体在酶II葡萄糖介导的转运和趋化性方面存在缺陷，但其他趋化反应正常。结论是，环鸟苷酸并不决定翻滚频率，可能不是转导途径的组成部分。环腺苷酸唯一已知的作用是参与一些受分解代谢物阻遏的蛋白质的合成。
