Simultaneous catabolite repression between glucose and toluene metabolism in Pseudomonas putida is channeled through different signaling pathways
Simultaneous catabolite repression between glucose and toluene metabolism in Pseudomonas putida is channeled through different signaling pathways
复制标题
DOI：
10.1128/jb.00679-07
复制
发表时间：
2007-09-01
影响因子：
3.2
通讯作者：
Ramos, Juan L.
中科院分区：
文献类型：
--
作者：
del Castillo, Teresa;Ramos, Juan L.
恶臭假单胞菌KT 2440（pWWO）可以通过TOL质粒编码的分解代谢途径使用甲苯，并可以通过一系列三种外周染色体编码的途径使用葡萄糖，将葡萄糖转化为6-磷酸葡萄糖酸（6 PG），即葡萄糖激酶途径，其中葡萄糖通过葡萄糖激酶和葡萄糖-6-磷酸脱氢酶的作用转化为6 PG。或者，葡萄糖可被氧化成葡糖酸盐，葡糖酸盐可被葡糖激酶磷酸化成6PG或氧化成2-酮葡糖酸盐，2-酮葡糖酸盐又转化成6PG。我们的研究结果表明，KT 2440同时代谢葡萄糖和甲苯，如[C-13]葡萄糖的净通量分析所揭示的。葡萄糖代谢中的葡萄糖激酶和葡糖激酶活性的测定、使用Pu TOL上游途径的启动子与'lacZ的融合的基因表达测定和全局转录组测定揭示了在使用这两种碳源时同时的分解代谢物阻遏。甲苯对葡萄糖代谢的影响针对葡萄糖激酶分支，不影响葡萄糖酸盐代谢。葡萄糖激酶途径和TOL途径的分解代谢物阻遏由两种不同的分解代谢物阻遏系统触发。Pu的表达主要通过PtsN被抑制，以响应高水平的2-氨基-3-脱氧葡萄糖酸-6-磷酸，而葡萄糖激酶途径的抑制通过Crc被引导。
Pseudomonas putida KT2440 (pWWO) can use toluene via the TOL plasmid-encoded catabolic pathways and can use glucose via a series of three peripheral chromosome-encoded routes that convert glucose into 6-phosphogluconate (6PG), namely, the glucokinase pathway, in which glucose is transformed to 6PG through the action of glucokinase and glucose-6-phosphate dehydrogenase. Alternatively, glucose can be oxidized to gluconate, which can be phosphorylated by gluconokinase to 6PG or oxidized to 2-ketogluconate, which, in turn, is converted into 6PG. Our results show that KT2440 metabolizes glucose and toluene simultaneously, as revealed by net flux analysis of [C-13]glucose. Determination of glucokinase and gluconokinase activities in glucose metabolism, gene expression assays using a fusion of the promoter of the Pu TOL upper pathway to 'lacZ, and global transcriptomic assays revealed simultaneous catabolite repression in the use of these two carbon sources. The effect of toluene on glucose metabolism was directed to the glucokinase branch and did not affect gluconate metabolism. Catabolite repression of the glucokinase pathway and the TOL pathway was triggered by two different catabolite repression systems. Expression from Pu was repressed mainly via PtsN in response to high levels of 2-dehydro-3-deoxygluconate-6-phosphate, whereas repression of the glucokinase pathway was channeled through Crc.