Department of Biomedical Science, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi, 110019, India.
Sci Rep. 2024 Aug 5;14(1):18073. doi: 10.1038/s41598-024-68636-9.
The escalating antibiotic resistance in mycobacterial species poses a significant threat globally, necessitating an urgent need to find alternative solutions. Bacteriophage-derived endolysins, which facilitate phage progeny release by attacking bacterial cell walls, present promising antibacterial candidates due to their rapid lytic action, high specificity and low risk of resistance development. In mycobacteria, owing to the complex, hydrophobic cell wall, mycobacteriophages usually synthesize two endolysins: LysinA, which hydrolyzes peptidoglycan; LysinB, which delinks mycolic acid-containing outer membrane and arabinogalactan, releasing free mycolic acid. In this study, we conducted domain analysis and functional characterization of a novel LysinB from RitSun, an F2 sub-cluster mycobacteriophage from our phage collection. Several key properties of RitSun LysinB make it an important antimycobacterial agent: its ability to lyse Mycobacterium smegmatis from without, a higher than previously reported specific activity of 1.36 U/mg and its inhibitory effect on biofilm formation. Given the impermeable nature of the mycobacterial cell envelope, dissecting RitSun LysinB at the molecular level to identify its cell wall-destabilizing sequence could be utilized to engineer other native lysins as fusion proteins, broadening their activity spectrum.
分枝杆菌物种中抗生素耐药性的不断升级在全球范围内构成了重大威胁，因此迫切需要寻找替代解决方案。噬菌体衍生的内溶素通过攻击细菌细胞壁促进噬菌体后代的释放，由于其快速裂解作用、高度特异性和低耐药风险，成为有前途的抗菌候选物。在分枝杆菌中，由于细胞壁复杂且疏水，分枝杆菌噬菌体通常合成两种内溶素：LysinA，它水解肽聚糖；LysinB，它使含有分枝菌酸的外膜和阿拉伯半乳聚糖脱连，释放游离的分枝菌酸。在这项研究中，我们对来自噬菌体库的 F2 亚群分枝杆菌噬菌体 RitSun 的一种新型 LysinB 进行了结构域分析和功能表征。 RitSun LysinB 的几个关键特性使其成为一种重要的抗分枝杆菌药物：它能够从外部裂解耻垢分枝杆菌，比之前报道的特异性活性 1.36 U/mg 更高，并且能够抑制生物膜形成。鉴于分枝杆菌细胞包膜的不可渗透性，在分子水平上剖析 RitSun LysinB 以鉴定其细胞壁破坏序列，可以用于工程化其他天然溶素作为融合蛋白，扩大其活性谱。
