Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur; CNRS UMR3528; CNRS USR3756, Paris, France.
Biological NMR Technological Platform, Center for Technological Resources and Research, Department of Structural Biology and Chemistry, Institut Pasteur; CNRS UMR3528, Paris, France.
J Biomol NMR. 2019 Jul;73(6-7):293-303. doi: 10.1007/s10858-019-00246-4. Epub 2019 May 23.
Secretion pili, bacterial fibers responsible for transporting proteins to the extracellular milieu in some secretion systems, are very strong structures but at the same time highly flexible. Their flexibility and helical symmetry make structure determination at atomic resolution a challenging task. We have previously used an integrative structural biology approach including liquid-state NMR, cryo-electron microscopy (cryo-EM), and modeling to determine the pseudo-atomic resolution structure of the type 2 secretion system pseudopilus in a mutant form, where we employed NMR to determine the high resolution structure of the pilin (the monomer building block of the pilus). In this work, we determine the pseudo-atomic structure of the wild type pilus, and compare the dynamics of wild type and mutant pili by normal mode analysis. We present a detailed NMR analysis of the dynamics of the pilin in isolation, and compare dynamics and solvent accessibility of isolated and assembled pilins by Hydrogen/Deuterium eXchange Mass Spectrometry (HDX-MS). These complementary approaches provide a comprehensive view of internal and overall dynamics of pili, crucial for their function.
分泌菌毛是某些分泌系统中负责将蛋白质运输到细胞外环境的细菌纤维，它们是非常强的结构，但同时又具有高度的灵活性。它们的灵活性和螺旋对称性使得在原子分辨率下进行结构测定成为一项具有挑战性的任务。我们之前使用了一种综合结构生物学方法，包括液相 NMR、低温电子显微镜（cryo-EM）和建模，来确定一种突变形式的 II 型分泌系统假菌毛的伪原子分辨率结构，我们使用 NMR 来确定菌毛（菌毛的单体构建块）的高分辨率结构。在这项工作中，我们确定了野生型菌毛的伪原子结构，并通过正常模式分析比较了野生型和突变型菌毛的动力学。我们对菌毛单体的动力学进行了详细的 NMR 分析，并通过氢/氘交换质谱（HDX-MS）比较了单体和组装菌毛的动力学和溶剂可及性。这些互补的方法提供了菌毛内部和整体动力学的全面视图，这对它们的功能至关重要。
