Molecular details of INH-C10 binding to wt KatG and Its S315T mutant.
Molecular details of INH-C10 binding to wt KatG and Its S315T mutant.
复制标题
INH-C10 与 wt KatG 及其 S315T 突变体结合的分子细节。
DOI：
10.1021/mp500736n
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发表时间：
2015
影响因子：
4.9
通讯作者：
Machuqueiro,Miguel
中科院分区：
文献类型：
--
作者：
Teixeira,VitorH;Ventura,Cristina;Leitão,Ruben;Ràfols,Clara;Bosch,Elisabeth;Martins,Filomena;Machuqueiro,Miguel
异烟肼(INH)仍然是两种最有效的抗结核药物之一，并被包括在所有推荐的多种治疗方案中。由于结核分枝杆菌对异烟肼的耐药性不断增加，主要与katG基因突变有关，已提出了新的异烟肼化合物来规避这一问题。在这项工作中，我们对wtKatG或其S315T突变形式与INH或INH-C10(一种新的酰化INH衍生物)之间相互作用的分子决定因素进行了详细的比较研究。分子动力学模拟探索了这两种蛋白质的构象空间，结果表明S315T突变对这些残基附近的通道平均大小没有显著影响。我们的模拟还表明，分配给Asp137的空间位阻作用是暂时的，静电变化对于理解KatG突变的酶活性数据可能是重要的。此外，分子对接研究被用来确定两种底物的首选结合模式。在突变后，明显不利于反应的对接溶液变得最丰富，这表明S315T突变倾向于不太理想的结合模式。此外，INH-C100中的脂肪族尾巴似乎使肼基团更接近血红素，因此无论酶的形式如何，都有利于明显的最活跃的结合模式。ITC的数据与我们对C10烷链作用的解释是一致的，并有助于合理地解释所观察到的INH-C10的实验MIC值显著较低的情况。这种化合物似乎能够抵消突变引起的大部分构象限制，这些限制被认为是突变菌株INH活性下降的原因。因此，异烟肼-C10是一种非常有前景的药物开发先导化合物。
Isoniazid (INH) is still one of the two most effective antitubercular drugs and is included in all recommended multitherapeutic regimens. Because of the increasing resistance ofMycobacterium tuberculosisto INH, mainly associated with mutations in thekatGgene, new INH-based compounds have been proposed to circumvent this problem. In this work, we present a detailed comparative study of the molecular determinants of the interactions betweenwtKatG or its S315T mutant form and either INH or INH-C10, a new acylated INH derivative. MD simulations were used to explore the conformational space of both proteins, and results indicate that the S315T mutation did not have a significant impact on the average size of the access tunnel in the vicinity of these residues. Our simulations also indicate that the steric hindrance role assigned to Asp137 is transient and that electrostatic changes can be important in understanding the enzyme activity data of mutations in KatG. Additionally, molecular docking studies were used to determine the preferred modes of binding of the two substrates. Upon mutation, the apparently less favored docking solution for reaction became the most abundant, suggesting that S315T mutation favors less optimal binding modes. Moreover, the aliphatic tail in INH-C10seems to bring the hydrazine group closer to the heme, thus favoring the apparent most reactive binding mode, regardless of the enzyme form. The ITC data is in agreement with our interpretation of the C10alkyl chain role and helped to rationalize the significantly lower experimental MIC value observed for INH-C10. This compound seems to be able to counterbalance most of the conformational restrictions introduced by the mutation, which are thought to be responsible for the decrease in INH activity in the mutated strain. Therefore, INH-C10appears to be a very promising lead compound for drug development.