Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523 United States.
Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, Michigan 48859 United States.
ACS Chem Biol. 2023 Mar 17;18(3):595-604. doi: 10.1021/acschembio.2c00912. Epub 2023 Mar 1.
Bacteria from the genus include pathogens that cause serious diseases in humans and remain as difficult infectious agents to treat. Central to these challenges are the composition and organization of the mycobacterial cell envelope, which includes unique and complex glycans. Inositol is an essential metabolite for mycobacteria due to its presence in the structural core of the immunomodulatory cell envelope glycolipids phosphatidylinositol mannoside (PIM) and PIM-anchored lipomannan (LM) and lipoarabinomannan (LAM). Despite their importance to mycobacterial physiology and pathogenesis, many aspects of PIM, LM, and LAM construction and dynamics remain poorly understood. Recently, probes that allow metabolic labeling and detection of specific mycobacterial glycans have been developed to investigate cell envelope assembly and dynamics. However, these tools have been limited to peptidoglycan, arabinogalactan, and mycolic acid-containing glycolipids. Herein, we report the development of synthetic azido inositol (InoAz) analogues as probes that can metabolically label PIMs, LM, and LAM in intact mycobacteria. Additionally, we leverage an InoAz probe to discover an inositol importer and catabolic pathway in . We anticipate that in the future, InoAz probes, in combination with bioorthogonal chemistry, will provide a valuable tool for investigating PIM, LM, and LAM biosynthesis, transport, and dynamics in diverse mycobacterial organisms.
包括引起人类严重疾病的病原体在内的 属细菌仍然是难以治疗的感染性病原体。这些挑战的核心是分枝杆菌细胞包膜的组成和组织，其中包括独特而复杂的聚糖。由于其存在于免疫调节细胞包膜糖脂（如磷脂酰肌醇甘露糖（PIM）和 PIM 锚定的脂甘露聚糖（LM）和脂阿拉伯甘露聚糖（LAM）的结构核心中，肌醇是分枝杆菌必需的代谢物。尽管它们对分枝杆菌的生理和发病机制很重要，但 PIM、LM 和 LAM 的结构和动态的许多方面仍然知之甚少。最近，开发了允许代谢标记和检测特定分枝杆菌聚糖的探针，以研究细胞包膜的组装和动态。然而，这些工具仅限于肽聚糖、阿拉伯半乳聚糖和含有类脂酸的糖脂。在此，我们报告了合成叠氮肌醇（InoAz）类似物作为探针的开发，该探针可代谢标记完整分枝杆菌中的 PIMs、LM 和 LAM。此外，我们利用 InoAz 探针在 中发现了一种肌醇转运体和分解代谢途径。我们预计，在未来，InoAz 探针与生物正交化学相结合，将为研究不同分枝杆菌生物体内 PIM、LM 和 LAM 的生物合成、运输和动态提供一种有价值的工具。
