Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, People's Republic of China.
Antimicrob Agents Chemother. 2022 Jan 18;66(1):e0146521. doi: 10.1128/AAC.01465-21. Epub 2021 Nov 15.
Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the most fatal diseases in the world. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the production of 5-methyltetrahydrofolate (5-CH-THF), which is required for the biosynthesis of methionine in bacteria. Here, we identified Rv2172c as an MTHFR in M. tuberculosis through and analyses and determined that the protein is essential for the growth of the bacterium. Subsequently, we constructed R159N and L214A mutants in M. tuberculosis and found that these mutants were more sensitive to the antifolates -aminosalicylic acid (PAS) and sulfamethoxazole (SMX). Combining biochemical and genetic methods, we found that R159N or L214A mutation impaired methionine production, leading to increased susceptibility of M. tuberculosis to PAS, which was largely restored by adding exogenous methionine. Moreover, overexpression of in M. tuberculosis could increase methionine production and lead to PAS resistance. This research is the first to identify an MTHFR in M. tuberculosis and reveals that the activity of this enzyme is associated with susceptibility to antifolates. These findings have particular value for antitubercular drug design for the treatment of drug-resistant TB.
结核病（TB）是由结核分枝杆菌引起的，是世界上最致命的疾病之一。亚甲基四氢叶酸还原酶（MTHFR）催化 5-甲基四氢叶酸（5-CH-THF）的生成，这是细菌内蛋氨酸生物合成所必需的。在这里，我们通过 和 分析鉴定出分枝杆菌中的 Rv2172c 是一种 MTHFR，并确定该蛋白对细菌的生长是必需的。随后，我们构建了分枝杆菌中的 R159N 和 L214A 突变体，并发现这些突变体对抗叶酸剂 -氨基水杨酸（PAS）和磺胺甲恶唑（SMX）更敏感。结合生化和遗传方法，我们发现 R159N 或 L214A 突变会损害蛋氨酸的产生，导致分枝杆菌对 PAS 的敏感性增加，而添加外源性蛋氨酸则在很大程度上恢复了敏感性。此外，在分枝杆菌中过表达 可以增加蛋氨酸的产生并导致 PAS 耐药。这项研究首次鉴定出分枝杆菌中的 MTHFR，并揭示了该酶的活性与抗叶酸剂的敏感性有关。这些发现对于设计治疗耐药性结核病的抗结核药物具有特殊价值。
