Department of Chemistry, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
Colloids Surf B Biointerfaces. 2012 Dec 1;100:163-8. doi: 10.1016/j.colsurfb.2012.05.011. Epub 2012 May 18.
While granulysin has been suggested to play an important role in adaptive immune responses against bacterial infections by killing pathogens, and molecular force for protein-protein interaction or protein-bacteria interaction may designate the specific functions of a protein, the molecular-force basis underlying the bacteriolytic effects of granulysin at single-molecule level remains unknown. Here, we produced and purified bactericidal domain of macaque granulysin (GNL). Our bacterial lysis assays suggested that GNL could efficiently kill bacteria such as Listeria monocytogenes. Furthermore, we found that the interaction force between GNL and L. monocytogenes measured by an atomic force microscopy (AFM) was about 22.5 pN. Importantly, our AFM-based single molecular analysis suggested that granulysin might lyse the bacteria not only through electrostatic interactions but also by hydrogen bonding and van der Waals interaction. Thus, this work provides a previous unknown mechanism for bacteriolytic effects of granulysin.
虽然颗粒溶素被认为通过杀死病原体在针对细菌感染的适应性免疫反应中发挥重要作用，并且蛋白质-蛋白质相互作用或蛋白质-细菌相互作用的分子力可能指定蛋白质的特定功能，但颗粒溶素在单分子水平上的溶菌作用的分子力基础仍然未知。在这里，我们生产并纯化了猕猴颗粒溶素（GNL）的杀菌结构域。我们的细菌裂解实验表明，GNL 可以有效地杀死李斯特菌等细菌。此外，我们发现原子力显微镜（AFM）测量的 GNL 与单核细胞增生李斯特菌之间的相互作用力约为 22.5 pN。重要的是，我们基于 AFM 的单分子分析表明，颗粒溶素不仅可以通过静电相互作用，还可以通过氢键和范德华相互作用来裂解细菌。因此，这项工作为颗粒溶素的溶菌作用提供了一个以前未知的机制。
