Mechanisms of Resistance Associated with the Inhibition of the Dehydration Step of Type II Fatty Acid Synthase in Mycobacterium tuberculosis.
Mechanisms of Resistance Associated with the Inhibition of the Dehydration Step of Type II Fatty Acid Synthase in Mycobacterium tuberculosis.
复制标题
DOI：
10.1021/acsinfecdis.9b00162
复制
发表时间：
2020-02-14
影响因子：
5.3
通讯作者：
Jackson M
中科院分区：
文献类型：
--
作者：
Grzegorzewicz AE;Gee C;Das S;Liu J;Belardinelli JM;Jones V;McNeil MR;Lee RE;Jackson M
Isoxyl（ISO）和thiacetazone（TAC）是两种抗结核前药，其通过抑制必需的FAS-II转化酶HadAB来阻断分枝菌酸的生物合成并杀死结核分枝杆菌（Mtb）。虽然阻止ISO和TAC转化为其活性形式或共价修饰其靶标的突变是与对两种药物的高水平耐药性相关的最常见的自发突变，但在第二种非必需的FAS-II还原酶HadBC中含有错义突变的Mtb菌株的高水平ISO和TAC耐药性的分子机制仍然无法解释。使用遗传，生物化学和生物物理方法和分子动力学模拟相结合，我们在这里表明，所有四个报告的耐药突变的HadBC的HadC亚基改变酶的稳定性和/或比活性，允许它在两种情况下（HadBCV 85 I和HadBCK 157 R），以弥补在整个结核分枝杆菌HadAB的缺陷。表达突变形式的HadC的Mtb菌株的分枝菌酸谱的分析进一步指出分枝菌酸生物合成复合物的活性的改变，并表明另外的贡献抗性机制，由此HadC突变可以降低HadAB对ISO和TAC的可及性。总的来说，我们的研究结果突出了开发FAS-II脱水步骤的优化抑制剂的重要性，该抑制剂能够同时抑制两种酶，这一目标可能是可以实现的，因为这两种酶的结构相似性及其对相同催化亚基HadB的依赖。
Isoxyl (ISO) and thiacetazone (TAC) are two antitubercular prodrugs that abolish mycolic acid biosynthesis and kill Mycobacterium tuberculosis (Mtb) through the inhibition of the essential FAS-II dehydratase, HadAB. While mutations preventing ISO and TAC from either being converted to their active form or from covalently modifying their target are the most frequent spontaneous mutations associated with high-level resistance to both drugs, the molecular mechanisms underlying the high-level ISO and TAC resistance of Mtb strains harboring missense mutations in the second, non-essential, FAS-II dehydratase HadBC remained unexplained. Using a combination of genetic, biochemical and biophysical approaches and molecular dynamics simulation, we here show that all four reported resistance mutations in the HadC subunit of HadBC alter the stability and/or specific activity of the enzyme, allowing it in two cases (HadBCV85I and HadBCK157R) to compensate for a deficiency in HadAB in whole Mtb bacilli. Analysis of the mycolic acid profiles of Mtb strains expressing the mutated forms of HadC further points to alterations in the activity of the mycolic acid biosynthetic complex and suggests an additional contributing resistance mechanism whereby HadC mutations may reduce the accessibility of HadAB to ISO and TAC. Collectively, our results highlight the importance of developing optimized inhibitors of the dehydration step of FAS-II capable of inhibiting both dehydratases simultaneously, a goal that may be achievable given the structural resemblance of the two enzymes and their reliance on the same catalytic subunit, HadB.
登录
查看更多内容
影响因子：
3.7
作者：
Coxon GD;Craig D;Corrales RM;Vialla E;Gannoun-Zaki L;Kremer L
通讯作者：
Kremer L
影响因子：
6.4
作者：
DeJesus MA;Gerrick ER;Xu W;Park SW;Long JE;Boutte CC;Rubin EJ;Schnappinger D;Ehrt S;Fortune SM;Sassetti CM;Ioerger TR
通讯作者：
Ioerger TR
影响因子：
3.6
作者：
Alahari, Anuradha;Alibaud, Laeticia;Kremer, Laurent
通讯作者：
Kremer, Laurent
影响因子：
4.9
作者：
Martin, A;Camacho, M;Palomino, JC
通讯作者：
Palomino, JC
影响因子：
3.6
作者：
Veyron-Churlet, R;Guerrini, O;Zerbib, D
通讯作者：
Zerbib, D