STRUCTURAL STUDIES OF BACTERIAL SIGNALLING: SPORULATION CONTROL

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 芽孢杆菌进入产孢期是由组氨酸激酶磷酸继电器控制的，这是原核生物主要信号转导机制的一个变体。SDA直接抑制产孢子组氨酸激酶对DNA损伤和复制缺陷的反应。我们测定了嗜热脂肪地质杆菌(GST)孢子形成激酶KinB与SDA络合的完整细胞质催化核心(包括二聚化和组氨酸磷酸转移，或DHP，连接到ATP结合催化，或CA，结构域)的2.0？分辨率的X射线晶体结构。结构和生化分析表明，SDA与DHP结构域的碱基结合，并通过充当简单的分子屏障来阻止与其结合的DHP结构域的分子交易。SDA可以立体地阻断自动磷酸化所需的CA和DHP结构域之间的通讯，也可以立体阻断反应调节因子Spo0F和磷酸转移和磷酸酶活性所需的DHP结构域之间的通讯。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Entry to sporulation in Bacilli is governed by a histidine kinase phosphorelay, a variation on the predominant signal transduction mechanism in prokaryotes. Sda directly inhibits sporulation histidine kinases in response to DNA damage and replication defects. We determined a 2.0 ¿-resolution X-ray crystal structure of the intact cytoplasmic catalytic core (comprising the Dimerization and Histidine-phosphotransfer, or DHp, domain, connected to the ATP-binding Catalytic, or CA, domain) of the Geobacillus stearothermophilus (Gst) sporulation kinase KinB complexed with Sda. Structural and biochemical analyses reveal that Sda binds to the base of the DHp domain and prevents molecular transactions with the DHp domain to which it is bound by acting as a simple molecular barricade. Sda acts to sterically block communication between the CA and DHp domains required for autophosphorylation, as well as to sterically block communication between the response regulator Spo0F and DHp domain required for phosphotransfer and phosphatase activities.