State Key Laboratory of Microbial Resources and CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci China Life Sci. 2022 May;65(5):1014-1023. doi: 10.1007/s11427-021-2000-2. Epub 2021 Oct 8.
Heptoses are important structural components of Gram-negative bacterium cell wall and participate in bacterial colonization, infection, and immune recognition. Current knowledge of NDP-heptose originating from D-sedoheptulose 7-phosphate in Grampositive bacterium remains limited. Here, in silico analysis suggested that the special tridomain NDP-heptose synthetases with isomerase, kinase, and nucleotidyltransferase activities are conservatively distributed in Actinobacteria class of Gram-positive bacterium. Enzymatical characterization of the tridomain proteins from different strains showed that they are involved in ADP-D-glycero-β-D-manno-heptose biosynthesis despite the unexpected discovery of kinase activities deficient in some proteins. The presence of three types of NDP-heptose synthetases in Gram-positive bacterium suggests that it is also a rich source of heptoses and the heptose moieties may play important roles in vivo. Our work updates the understanding of NDP-heptose biosynthesis in Gram-positive bacterium and lays a solid foundation for further physiological function explorations.
庚糖是革兰氏阴性菌细胞壁的重要结构成分，参与细菌定植、感染和免疫识别。目前对革兰氏阳性菌中来源于 D-赤藓糖 7-磷酸的 NDP-庚糖的了解仍然有限。本文通过计算机分析表明，具有异构酶、激酶和核苷酸转移酶活性的特殊三域 NDP-庚糖合成酶在革兰氏阳性菌放线菌目中保守分布。来自不同菌株的三域蛋白的酶学特性表明，它们参与 ADP-D-甘油-β-D-甘露庚糖的生物合成，尽管在一些蛋白中发现了激酶活性缺失的意外情况。革兰氏阳性菌中存在三种类型的 NDP-庚糖合成酶，这表明它也是庚糖的丰富来源，庚糖部分可能在体内发挥重要作用。我们的工作更新了对革兰氏阳性菌中 NDP-庚糖生物合成的认识，并为进一步的生理功能探索奠定了坚实的基础。
