Manson M D, Blank V, Brade G, Higgins C F
Nature. 1986;321(6067):253-6. doi: 10.1038/321253a0.
Bacterial chemotaxis provides a simple model system for the more complex sensory responses of multicellular eukaryotic organisms. In Escherichia coli, methylation and demethylation of four related membrane proteins, the methyl-accepting chemotaxis proteins (or MCPs), is central to chemotactic sensing and signal transduction. Three of these proteins, Tar, Tsr and Trg, have been assigned specific roles in chemotaxis. However, the role of the fourth MCP, Tap, has remained obscure. We demonstrate here that Tap functions as a conventional signal transducer, enabling the cell to respond chemotactically to dipeptides. This provides the first evidence of specific bacterial chemotaxis towards peptides. Peptide taxis requires the function of a periplasmic component of the dipeptide permease. This protein represents the first example of a periplasmic chemoreceptor that does not have a sugar substrate.
细菌趋化作用为多细胞真核生物更复杂的感官反应提供了一个简单的模型系统。在大肠杆菌中，四种相关膜蛋白，即甲基接受趋化蛋白（或MCPs）的甲基化和去甲基化，对于趋化传感和信号转导至关重要。其中三种蛋白，Tar、Tsr和Trg，已被确定在趋化作用中具有特定作用。然而，第四种MCP，Tap的作用仍不清楚。我们在此证明，Tap作为一种传统的信号转导器发挥作用，使细胞能够对二肽做出趋化反应。这为细菌对肽的特异性趋化作用提供了首个证据。肽趋化作用需要二肽通透酶的周质成分发挥作用。这种蛋白代表了第一个没有糖底物的周质化学感受器的例子。
