Khan Muhammad Tahir, Chinnasamy Sathishkumar, Cui Zhilei, Irfan Muhammad, Wei Dong-Qing
Department of Bioinformatics and Biosciences, Capital University of Science and Technology, Pakistan.
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, and Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China.
Saudi J Biol Sci. 2020 Nov;27(11):3150-3156. doi: 10.1016/j.sjbs.2020.07.015. Epub 2020 Jul 17.
Pyrazinamide (PZA) is a component of first-line drugs, active against latent (MTB) isolates. The prodrug is activated into the active form, pyrazinoic acid (POA) via gene-encoded pyrazinamidase (PZase). Mutations in have been reported, most commonly responsible for PZA-resistance in more than 70% of the resistant cases. In our previous study, we detected many mutations in PZase among PZA-resistance MTB isolates including A46V, H71Y, and D129N. The current study was aimed to investigate the molecular mechanism of PZA-resistance behind mutants (MTs) A46V, H71Y, and D129N in comparison with the wild type (WT) through molecular dynamic (MD) simulation. MTB positive samples were subjected to PZA drug susceptibility testing (DST) against critical concentration (100ug/ml). The resistant samples were subjected to sequencing. Thirty-six various mutations have been observed in the coding region of of PZA-resistant isolates (GenBank accession No. MH461111) including A46V, H71Y, and D129N. The post-simulation analysis revealed a significant variation in MTs structural dynamics as compared to the WT. Root means square deviations (RMSD) and Root means square fluctuation (RMSF) has been found in variation between WT and MTs. Folding effect and pocket volume were altered in MTs when compared with WT. Geometric matching supports the effect of mutation A46V, H71Y, and D129N on PZase structure that may have an insight effect on PZase dynamics, making them vulnerable to convert pro-PZA into active form, POA. In conclusion, the current analyses will provide useful information behind PZA-resistance for better management of drug-resistant TB.
吡嗪酰胺（PZA）是一线药物的组成部分，对潜伏性结核分枝杆菌（MTB）分离株具有活性。前药通过基因编码的吡嗪酰胺酶（PZase）激活为活性形式吡嗪酸（POA）。已报道了pncA基因的突变，在70%以上的耐药病例中，这些突变是导致PZA耐药的最常见原因。在我们之前的研究中，我们在耐PZA的MTB分离株中检测到PZase的许多突变，包括A46V、H71Y和D129N。本研究旨在通过分子动力学（MD）模拟，与野生型（WT）相比，研究突变体（MTs）A46V、H71Y和D129N背后的PZA耐药分子机制。对MTB阳性样本进行针对临界浓度（100μg/ml）的PZA药物敏感性试验（DST）。对耐药样本进行pncA测序。在耐PZA分离株（GenBank登录号MH461111）的pncA编码区观察到36种不同的突变，包括A46V、H71Y和D129N。模拟后分析显示，与WT相比，MTs的结构动力学有显著变化。在WT和MTs之间发现了均方根偏差（RMSD）和均方根波动（RMSF）的变化。与WT相比，MTs中的折叠效应和口袋体积发生了改变。几何匹配支持突变A46V、H71Y和D129N对PZase结构的影响，这可能对PZase动力学有深入影响，使其难以将前体PZA转化为活性形式POA。总之，目前的分析将为更好地管理耐多药结核病提供PZA耐药背后的有用信息。
