School of Life Sciences , University of Warwick , Coventry , West Midlands CV4 7AL , United Kingdom.
School of Pharmacy , University of East Anglia , Norwich Research Park, Norwich , Norfolk NR4 7TJ , United Kingdom.
ACS Chem Biol. 2019 Sep 20;14(9):1879-1887. doi: 10.1021/acschembio.9b00204. Epub 2019 Aug 21.
() is the causative agent of tuberculosis (TB) and has evolved an incredible ability to survive latently within the human host for decades. The pathogen encodes for a low number of ATP-binding cassette (ABC) importers for the acquisition of carbohydrates that may reflect the nutrient poor environment within the host macrophages. UgpB (Rv2833c) is the substrate binding domain of the UgpABCE transporter that recognizes glycerophosphocholine (GPC), indicating that this transporter has a role in recycling glycerophospholipid metabolites. By using a combination of saturation transfer difference (STD) NMR and X-ray crystallography, we report the structural analysis of UgpB complexed with GPC and have identified that UgpB not only recognizes GPC but is also promiscuous for a broad range of glycerophosphodiesters. Complementary biochemical analyses and site-directed mutagenesis precisely define the molecular basis and specificity of glycerophosphodiester recognition. Our results provide critical insights into the structural and functional role of the UgpB transporter and reveal that the specificity of this ABC-transporter is not limited to GPC, therefore optimizing the ability of to scavenge scarce nutrients and essential glycerophospholipid metabolites via a single transporter during intracellular infection.
（）是结核病（TB）的病原体，它具有令人难以置信的能力，可以在人类宿主中潜伏数十年。该病原体编码了少量的 ATP 结合盒（ABC）进口器，用于获取碳水化合物，这可能反映了宿主巨噬细胞内营养贫乏的环境。UgpB（Rv2833c）是 UgpABCE 转运体的底物结合结构域，可识别甘油磷酸胆碱（GPC），表明该转运体在回收甘油磷脂代谢物方面发挥作用。通过结合饱和转移差（STD）NMR 和 X 射线晶体学，我们报告了 UgpB 与 GPC 复合物的结构分析，并确定 UgpB 不仅识别 GPC，而且还对广泛的甘油磷酸二酯具有混杂性。互补的生化分析和定点突变精确地定义了甘油磷酸二酯识别的分子基础和特异性。我们的研究结果为 UgpB 转运体的结构和功能作用提供了重要的见解，并揭示了该 ABC 转运体的特异性不仅限于 GPC，因此优化了在细胞内感染期间通过单个转运体来获取稀缺营养和必需甘油磷脂代谢物的能力。
