Characterization of trigger enzymes involved in the regulation and function of sRNAs in B. subtilis

到目前为止，只有少数所谓的触发酶是已知的。这些是代谢酶，实现控制基因表达的第二个功能。迄今为止已知的触发酶可以结合DNA并作为转录因子，通过结合RNA影响RNA的稳定性，通过磷酸化修饰蛋白质或通过蛋白质/蛋白质相互作用抑制转录因子。此外，与大肠杆菌和其他革兰氏阴性菌相比，我们对革兰氏阳性菌（尤其是枯草芽孢杆菌）中的sRNAs及其靶点知之甚少。在后一种细菌中，仅鉴定了5个sRNAs靶点，其中包括我们研究的SR1和SR4两个sRNAs。在这个项目中，我们希望a)表征一种新的触发酶，丙酮酸羧化酶a (PycA)，最近在我们的团队中被确定为sRNA SR1的第二调节剂，详细介绍了生物化学和它的生物学作用。应阐明其作用机制及其作用的结构和生物学前提。c)证明枯草芽孢杆菌的甘油醛-3-磷酸脱氢酶GapA也是一种触发酶（一种RNase或与RNase或降解体组分相互作用的蛋白质），其功能由SR1d编码的小肽SR1P调节)，进一步鉴定出稳定性依赖于GapA的rna。并探讨GapA对这些rna的作用机制。

So far, only a few so called trigger enzymes are known. These are metabolic enzymes that fulfill a second function in control of gene expression. Trigger enzymes known to date can e.g. bind DNA and act as transcription factors, affect the stability of RNA by binding it, modify proteins by e.g. phosphorylation or inhibit transcription factors by protein/protein interactions. Furthermore, compared to E. coli and other Gram-negative bacteria, not so much is known about sRNAs and their targest in Gram-positive bacteria, in particular B. subtilis. In the latter bacterium, only for five sRNAs targets have been identified, among them for the two sRNAs SR1 and SR4 investigated in our group.In this project we want toa) characterize a novel trigger enzyme, pyruvate carboxylase A (PycA) recently identified in our group as second regulator of the sRNA SR1, in great detail biochemically and concerning its biological role. Both the mechanism of action and the structural and biological prerequisites for its action should be elucidated.b) identify further targets of PycA and analyse the action of this trigger enzymes at the promoters of these target gens.c) demonstrate that glyceraldehyde-3-phosphate-dehydrogenase GapA from B. subtilis is also a trigger enzyme (either a RNase or a protein that interacts with an RNAse or components of the degradosome), whose function is modulated by the small peptide SR1P encoded by SR1d) identify further RNAs whose stability depends on GapA, and investigate the mechanism of action of GapA at these RNAs.