结核分枝杆菌(Mtb),结核病的病原体,仍然是全球发病率和死亡率的主要诱因。Mtb已经进化出识别不同信号的机制,例如吞噬溶酶体内的酸性pH,因此重新编程多个生理和代谢过程以适应细胞内存活。此外,赖氨酸丙二酰被认为参与碳代谢酶的调节。然而,Mtb中的赖氨酸丙二酸化及其与酸性pH相关的代谢适应的关联仍然未知。这里,我们系统地表征了模拟溶酶体pH值的正常(7H9-Tyloxapol(Ty)-7.4)和酸性(7H9-Ty-4.5)培养基中生长的MtbH37Rv的比较丙二糖。总的来说,确定了1026种蛋白质中的2467个赖氨酸丙二酸位点,与不同的生物过程有关,特别是在代谢过程中积累。来自562个蛋白质的1090个赖氨酸丙二基化位点被定量,其中273个蛋白中391个赖氨酸丙二酸位点下调,36个蛋白中40个赖氨酸丙二酸位点上调,表明丙二基化可能参与酸性pH相关代谢。因此,与正常条件相比,在酸性胁迫下,GlcB的酶活性降低,对应于GlcB的丙二酸化降低,这进一步通过位点特异性突变得到证明。我们进一步发现Mtb-CobB,sirtuin样脱乙酰酶和脱琥珀酶,参与去丙二醛酶活性。一起,Mtbmalonylome不仅表明了丙二酸在代谢调节中的关键作用,但可能提供了新的见解丙二酰代谢适应体内酸性微环境。
Mycobacterium tuberculosis (Mtb), the pathogenic agent of tuberculosis, remains a primary inducement of morbidity and mortality globally. Mtb have evolved mechanisms to recognize diverse signals, such as acidic pH within phagolysosomes and therefore to reprogram multiple physiological and metabolic processes to adapt to intracellular survival. Moreover, lysine malonylation has been suggested to participate in regulation of enzymes in carbon metabolism. However, lysine malonylation in Mtb and its association with acidic pH associated metabolism adaptation remain unknown. Here, we systematically characterized the comparative malonylome of Mtb H37Rv grown in normal (7H9-Tyloxapol (Ty)-7.4) and acidic (7H9-Ty-4.5) medium mimicking lysosome pH. In total, 2467 lysine malonylation sites within 1026 proteins were identified, which related to diverse biological processes, particularly accumulated in metabolic process. 1090 lysine malonylation sites from 562 proteins were quantified, among which 391 lysine malonylation sites in 273 protein were down-regulated while 40 lysine malonylation sites from 36 proteins were up-regulated in acidic medium, indicating that malonylation may participate in acidic pH associated metabolism. Accordingly, the enzyme activity of GlcB was reduced under acidic stress corresponding to decreased malonylation of GlcB compared with that of normal condition and this was further demonstrated by site-specific mutations. We further found that Mtb-CobB, a sirtuin-like deacetylase and desuccinylase, involved in demalonylase activity. Together, the Mtb malonylome not only indicates the critical role of malonylation in metabolism regulation, but may provide new insights of malonylation on metabolism adaptation to acidic micro-environment in vivo.