Regulation of glutamine and glutamate metabolism by GlnR and GlnA in Streptococcus pneumoniae
Regulation of glutamine and glutamate metabolism by GlnR and GlnA in Streptococcus pneumoniae
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DOI：
10.1074/jbc.m601661200
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Kuipers, Oscar P.
中科院分区：
文献类型：
--
作者：
Kloosterman, Tomas G.;Hendriksen, Wouter T.;Kuipers, Oscar P.
已知参与氮代谢的几个基因有助于致病细菌的毒力。在这里，我们研究了氮调节蛋白GlnR在革兰氏阳性人类病原体肺炎链球菌中的功能。我们表明，GlnR介导的基因参与谷氨酰胺合成和摄取（glnA和glnPQ），谷氨酸合成（gdhA），和编码戊糖磷酸途径酶ZWF，形成一个操纵子与glnPQ的基因的转录抑制。此外，gdhA的表达也受到多效性调节因子CodY的抑制。GlnR依赖性调节通过保守的操纵子序列发生，并对生长培养基中谷氨酸、谷氨酰胺和铵的浓度作出响应。通过体外结合研究和转录分析，我们发现GlnR的调节功能依赖于GlnA。GlnA和GlnB突变体对Detroit 562人咽上皮细胞的粘附力显著降低，表明这些基因在S.肺炎。因此，我们的研究结果提供了一个全面的了解谷氨酰胺和谷氨酸代谢的调控S。肺炎链球菌由GlnR和GlnA介导。
Several genes involved in nitrogen metabolism are known to contribute to the virulence of pathogenic bacteria. Here, we studied the function of the nitrogen regulatory protein GlnR in the Gram-positive human pathogen Streptococcus pneumoniae. We demonstrate that GlnR mediates transcriptional repression of genes involved in glutamine synthesis and uptake (glnA and glnPQ), glutamate synthesis (gdhA), and the gene encoding the pentose phosphate pathway enzyme Zwf, which forms an operon with glnPQ. Moreover, the expression of gdhA is also repressed by the pleiotropic regulator CodY. The GlnR-dependent regulation occurs through a conserved operator sequence and is responsive to the concentration of glutamate, glutamine, and ammonium in the growth medium. By means of in vitro binding studies and transcriptional analyses, we show that the regulatory function of GlnR is dependent on GlnA. Mutants of glnA and glnP displayed significantly reduced adhesion to Detroit 562 human pharyngeal epithelial cells, suggesting a role for these genes in the colonization of the host by S. pneumoniae. Thus, our results provide a thorough insight into the regulation of glutamine and glutamate metabolism of S. pneumoniae mediated by both GlnR and GlnA.