Instituto de Biomedicina de Valencia-Consejo Superior de Investigaciones Científicas (IBV-CSIC) and Centro de Investigaciones en Red de Enfermedades Raras (CIBERER-ISCIII), Jaume Roig 11, Valencia 46010, Spain.
Curr Opin Struct Biol. 2010 Dec;20(6):763-71. doi: 10.1016/j.sbi.2010.09.010. Epub 2010 Oct 13.
Two-component systems, composed of a homodimeric histidine kinase (HK) and a response regulator (RR), are major signal transduction devices in bacteria. Typically the signal triggers HK autophosphorylation at one His residue, followed by phosphoryl transfer from the phospho-His to an Asp residue in the RR. Signal extinction frequently involves phospho-RR dephosphorylation by a phosphatase activity of the HK. Our understanding of these reactions and of the determinants of partner specificity among HK-RR couples has been greatly increased by recent crystal structures and biochemical experiments on HK-RR complexes. Cis-autophosphorylation (one subunit phosphorylates itself) occurs in some HKs while trans-autophosphorylation takes place in others. We review and integrate this new information, discuss the mechanism of the three reactions and propose a model for transmembrane signaling by these systems.
双组分系统由一个同二聚体组氨酸激酶 (HK) 和一个反应调节蛋白 (RR) 组成，是细菌中主要的信号转导装置。通常，信号触发 HK 在一个 His 残基上自动磷酸化，然后将磷酸基团从磷酸化的 His 转移到 RR 中的一个 Asp 残基上。信号的衰减通常涉及 HK 的磷酸酶活性对磷酸化 RR 的去磷酸化。最近对 HK-RR 复合物的晶体结构和生化实验极大地增加了我们对这些反应以及 HK-RR 对之间伴侣特异性决定因素的理解。一些 HK 发生顺式自动磷酸化（一个亚基自身磷酸化），而另一些则发生反式自动磷酸化。我们综述和整合了这些新信息，讨论了这三种反应的机制，并提出了一个模型，用于这些系统的跨膜信号传递。
