The potassium-sensory mechanism of a prokaryotic histidine kinase/response regulator system

细菌通过使用所谓的双组分系统来感知和响应各种压力条件。这些系统由一个组氨酸激酶和一个反应调节因子组成，它们感知环境刺激，通过磷酸化传递信息并诱导细胞反应。例如，大肠杆菌就含有32个这样的系统。其中，KdpD/ kdpe系统编码在1000多个已测序的细菌和古细菌基因组中，包括许多致病生物。KdpD将被用作传感器组氨酸激酶家族的代表，以深入了解传感和信号传导过程中的蛋白质结构和动力学。因此，阐明KdpD中K+传感的结构基础和分子机制将是本项目的目标。解析全长KdpD和分离域的三维结构。此外，我们将测试一种新的KdpD刺激感知模型，即双K+结合位点模型。最后，组氨酸激酶信号传导过程中的构象动力学将使用基于Foerster共振能量转移（FRET）的方法进行监测。该项目的工作将有助于更好地理解K+反应组氨酸激酶的分子机制，以及阐明蛋白质中K+结合基序。

Bacteria sense and respond to various stress conditions by employing so called two-component systems. These systems consist of a histidine kinase and a response regulator, which sense environmental stimuli, transduce information via phosphorylation and induce a cellular response. Escherichia coli, for example, contains 32 of these systems. One of which, the K+-responsive KdpD/KdpE-system, is encoded in more than 1000 sequenced bacterial and archaeal genomes including many pathogenic organisms. KdpD will be used as representative of the sensor histidine kinase family to obtain insights into protein structure and dynamics during sensing and signaling. Therefore, it will be the aim of the project to elucidate the structural basis and the molecular mechanism of K+-sensing in KdpD. The 3D-structure of full-length KdpD and of separated domains shall be resolved. Furthermore, we shall test a new stimulus perception model for KdpD, the dual K+-binding site model. Finally, conformational dynamics during signaling within the histidine kinase shall be monitored using a Foerster resonance energy transfer (FRET)-based approach. Work on this project will contribute both to a better understanding of the molecular mechanism of a K+-responsive histidine kinase as well to the elucidation of K+-binding motifs in proteins in general.