Analysis of Regulatory Mechanism Controlling Tryptophan Metabolism in Bacteria

细菌色氨酸代谢调控机制分析

• 批准号: 0093023
• 负责人: Charles Yanofsky
• 金额: $ 79.71万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0093023&HistoricalAwards=false
• 关键词: Analysis; Regulatory; Mechanism; Controlling; Tryptophan

0093023 Charles YanofskyThis research will focus on three principle objectives. The first objective is to characterize the YczA regulatory protein of Bacillus subtilis and determine how it inactivates the TRAP regulatory protein. The TRAP protein regulates transcription of six of the tryptophan biosynthetic genes, it regulates the seventh trp gene translationally. The YczA protein is produced by the yczA-ycbK operon, an operon of previously unknown function. This operon is regulated by transcription attenuation; it is transcriptionally activated in response to the accumulation of uncharged tRNATrp. The second objective is to continue studies on the detailed features of the mechanism of transcription attenuation used by E. coli and other bacterial species to regulate expression of the degradative tryptophanase(tna) operon. Tryptophan addition to E. coli cultures induces expression of the tna operon. Induction leads to inhibition of cleavage of a leader peptidyl-tRNA and this inhibition stalls the translating ribosome. The stalled ribosome prevents Rho mediated transcription termination in the leader region of the tna operon. The PI's laboratory has successfully reproduced the regulatory features for this operon in vitro and now plan to examine in detail exactly how peptidyl-tRNA cleavage is blocked. The third objective is to use DNA microarray analyses with the entire genome of Bacillus subtilis to determine which genes are selectively transcriptionally activated and transcriptionally inhibited in response to changes in tryptophan metabolism, as the PI recently did with the genome of E. coli. These findings should allow the comparison of expression of the genes of tryptophan metabolism in two microorganisms that are preferred subjects for experimental analysis.

0093023 Charles Yanofsky这项研究将集中在三个主要目标上。 第一个目标是表征枯草芽孢杆菌的YczA调节蛋白，并确定其如何使TRAP调节蛋白失活。 TRAP蛋白调节色氨酸生物合成基因中的六个的转录，其特异性地调节第七个trp基因。 YczA蛋白由yczA-ycbK操纵子产生，这是一种功能此前未知的操纵子。 该操纵子受转录衰减的调节;它响应于不带电荷的tRNATrp的积累而被转录激活。第二个目标是继续研究E.大肠杆菌和其它细菌物种来调节降解性内切酶（tna）操纵子的表达。色氨酸添加到E.大肠杆菌培养物诱导tna操纵子的表达。诱导导致前导肽基-tRNA切割的抑制，并且这种抑制使翻译核糖体停止。停滞的核糖体阻止Rho介导的tna操纵子前导区的转录终止。PI的实验室已经成功地在体外复制了这种操纵子的调控特征，现在计划详细研究肽基-tRNA切割是如何被阻断的。第三个目标是使用枯草芽孢杆菌全基因组的DNA微阵列分析，以确定哪些基因响应色氨酸代谢的变化而被选择性地转录激活和转录抑制，正如PI最近对E.杆菌 这些发现应该允许在两种微生物中色氨酸代谢基因的表达的比较，这两种微生物是实验分析的优选对象。