Structure of Sporulation Proteins in Bacillus subtilis

细菌、真菌和植物通过双组分信号转导系统和磷继电器来识别和响应大量的环境、代谢和细胞周期信号。这些系统调节各种基因和操纵子，从基本功能和毒力决定因素到果实的发育和成熟。信号输入激活atp依赖的激酶组氨酸残基的自磷酸化，信号在这些系统中的传播涉及到细菌孢子形成过程中发现的His-Asp磷酸转移，已经成为广泛的遗传和生化研究的主题。该通路组分的结构分析显示了这些信号蛋白如何相互作用，并给出了残基决定分子识别特异性的第一个观点。本研究的目的是利用晶体学技术结合生化和遗传分析，详细阐明磷接力中分子识别的性质、分子特异性和磷转移的机制。两个重点领域将是最终转录因子Spo0A的结构及其与DNA的相互作用，以及调节磷接力中磷酸化输入的信号感应组氨酸激酶的结构。后者的目的是了解信号配体相互作用激活激酶活性的机制。通过这些研究，将了解从信号配体结合到基因活化的信号转导通路的完整机制。

Bacteria, fungi and plants recognize and respond to a multitude of environmental, metabolic and cell cycle signals through two-component signal transduction system and phosphorelays. These systems regulate a variety of genes and operons ranging from essential functions and virulence determinants to development and the ripening of fruit. Signal input activates an ATP-dependent autophosphorylation of a histidine residue of a kinase and signal propagation in these systems involves His-Asp phosphotransfer discovered, that of sporulation in bacteria, has been the subject of extensive genetic and biochemical studies. Structural analysis of the components of the pathway have shown how these signaling proteins interact and have given a first view of what residues determine specificity of molecular recognition. The objectives of the present proposal are to elucidate in detail the nature of molecular recognition, molecular specificity, and the mechanism of phosphotransfer in the phosphorelay using crystallographic techniques in conjunction with biochemical and genetic analyses. Two areas of focus will be the structure of the ultimate transcription factor, Spo0A, and its interaction with DNA and the structure of the signal-sensing histidine kinase that regulates phosphoryl input in the phosphorelay. The objective of this latter aim is to understand the mechanism by which signal ligand interaction activates kinase activity. Through these studies the complete mechanism of the pathway of signal transduction from signal ligand binding to gene activation will be understood.