Background: Drug-resistant tuberculosis remains a health security threat and resistance to second-line drugs limits the options for treatment. Consequently, there is an utmost need for identifying and characterizing new biomarkers/drug targets of prime importance. Membrane proteins have an anticipated role in biological processes and could qualify as biomarkers/drug targets. Streptomycin (SM) is recommended as a second-line treatment regimen only when amikacin resistance has been confirmed. As extensively drug-resistant (XDR) isolates are frequently cross-resistant to second-line injectable drugs, an untapped potential for the continued use of SM has been suggested. Objective: The study aimed to analyze the membrane proteins overexpressed in SM resistant isolates of Mycobacterium tuberculosis using proteomics approaches. Methods: Membrane proteins were extracted employing sonication and ultracentrifugation. Twodimensional gel electrophoresis (2DGE) of membrane proteins was performed and identification of proteins was done by liquid chromatography-mass spectrometry (LCMS) and bioinformatics tools. Results: On analyzing the two-dimensional (2D) gels, five protein spots were found overexpressed in the membrane of SM resistant isolates. Docking analysis revealed that SM might bind to the conserved domain of overexpressed proteins and Group-based prediction system-prokaryotic ubiquitinlike protein (GPS-PUP) predicted potential pupylation sites within them. Conclusion: These proteins might be of diagnostic importance for detecting the cases early and for exploring effective control strategies against drug-resistant tuberculosis, particularly SM.

中文翻译：

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耐链霉素结核分枝杆菌分离株膜蛋白分析

背景：耐药结核病仍然是健康安全的威胁，对二线药物的耐药性限制了治疗的选择。因此，迫切需要识别和表征最重要的新生物标志物/药物靶标。膜蛋白在生物过程中具有预期的作用，可以作为生物标志物/药物靶标。只有在确认阿米卡星耐药后，才推荐链霉素 (SM) 作为二线治疗方案。由于广泛耐药 (XDR) 分离株经常与二线注射药物交叉耐药，因此有人提出继续使用 SM 的未开发潜力。目的：本研究旨在利用蛋白质组学方法分析结核分枝杆菌 SM 耐药菌株中过表达的膜蛋白。方法：采用超声处理和超速离心法提取膜蛋白。对膜蛋白进行二维凝胶电泳 (2DGE)，并通过液相色谱-质谱 (LCMS) 和生物信息学工具对蛋白质进行鉴定。结果：在分析二维 (2D) 凝胶时，发现五个蛋白质点在 SM 抗性分离株的膜中过度表达。对接分析显示 SM 可能与过表达蛋白的保守结构域结合，基于组的预测系统 - 原核泛素样蛋白 (GPS-PUP) 预测了其中潜在的 pupylation 位点。结论：这些蛋白质对于早期发现病例和探索针对耐药结核病，特别是 SM 的有效控制策略可能具有重要的诊断意义。