The OtsAB pathway is essential for trehalose biosynthesis in Mycobacterium tuberculosis
The OtsAB pathway is essential for trehalose biosynthesis in Mycobacterium tuberculosis
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DOI：
10.1074/jbc.m414232200
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发表时间：
2005-04-15
影响因子：
4.8
通讯作者：
Robertson, BD
中科院分区：
文献类型：
--
作者：
Murphy, HN;Stewart, GR;Robertson, BD
二糖海藻糖是分枝杆菌细胞质中的主要游离糖;它是细胞壁糖脂的组分，并且在细胞壁生物发生期间在分枝菌酸转运中起作用。海藻糖在结核分枝杆菌生物学中的多效性作用及其在哺乳动物细胞中的缺失表明其生物合成可能为新型药物提供有用的靶点。然而，海藻糖在M.结核病，本研究的目的是将突变引入每个途径，以确定它们是否在功能上是冗余的。结果表明，由葡萄糖和葡萄糖-6-磷酸生成海藻糖的OtsAB途径是M.在实验室培养中的结核菌生长和在小鼠模型中的毒力。在M.在结核病中，只有OtsB 2（Rv 3372）在该途径中具有功能性作用。OtsB 2，海藻糖-6-磷酸磷酸酶，是严格的生长所必需的，并提供了一个易于处理的高通量筛选的目标。TreYZ途径可以从α-1，4-连接的葡萄糖聚合物产生海藻糖，其失活对M.在体外或在小鼠中的结核病。treS基因的缺失改变了M.在小鼠中的肺结核，显著增加了慢性感染模型中的死亡时间。由于TreS酶催化海藻糖和麦芽糖的相互转化，小鼠表型可以反映合成额外海藻糖的需要，或者相反，需要分解储存的海藻糖以释放游离葡萄糖。
The disaccharide trehalose is the major free sugar in the cytoplasm of mycobacteria; it is a constituent of cell wall glycolipids, and it plays a role in mycolic acid transport during cell wall biogenesis. The pleiotropic role of trehalose in the biology of Mycobacterium tuberculosis and its absence from mammalian cells suggests that its biosynthesis may provide a useful target for novel drugs. However, there are three potential pathways for trehalose biosynthesis in M. tuberculosis, and the aim of the present study was to introduce mutations into each of the pathways to determine whether or not they are functionally redundant. The results show that the OtsAB pathway, which generates trehalose from glucose and glucose-6-phosphate, is the dominant pathway required for M. tuberculosis growth in laboratory culture and for virulence in a mouse model. Of the two otsB homologues annotated in the genome sequence of M. tuberculosis, only OtsB2 (Rv3372) has a functional role in the pathway. OtsB2, trehalose-6-phosphate phosphatase, is strictly essential for growth and provides a tractable target for high throughput screening. Inactivation of the TreYZ pathway, which can generate trehalose from alpha-1,4-linked glucose polymers, had no effect on the growth of M. tuberculosis in vitro or in mice. Deletion of the treS gene altered the late stages of pathogenesis of M. tuberculosis in mice, significantly increasing the time to death in a chronic infection model. Because the TreS enzyme catalyzes the interconversion of trehalose and maltose, the mouse phenotype could reflect either a requirement for synthesis of additional trehalose or, conversely, a requirement for breakdown of stored trehalose to liberate free glucose.