STRUCTURAL STUDIES OF BACTERIAL SIGNALLING: SPORULATION CONTROL

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 进入芽孢杆菌中的孢子形成受组氨酸激酶磷酸化介导，这是原核生物中主要信号转导机制的变体。SDA直接抑制孢子形成组氨酸激酶对DNA损伤和复制缺陷的反应。我们确定了与Sda复合的嗜热脂肪土芽孢杆菌（Gst）孢子形成激酶KinB的完整细胞质催化核心（包括连接到ATP结合催化或CA结构域的二聚化和组氨酸磷酸转移或DHp结构域）的2.0 <$-分辨率X射线晶体结构。结构和生物化学分析表明，Sda结合到DHp结构域的基础上，并防止与DHp结构域的分子交易，它是作为一个简单的分子屏障结合。SDA的作用是在空间上阻断CA和DHp结构域之间的通讯，这是自磷酸化所必需的，以及在空间上阻断反应调节剂Spo 0 F和DHp结构域之间的通讯，这是磷酸转移和磷酸酶活性所必需的。

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.