Dynamics of a type 2 secretion system pseudopilus unraveled by complementary approaches

Benjamin Bardiaux (1, 2) , Florence Cordier (1, 3) , Sébastien Brier (3) , Aracelys López-Castilla (1) , Nadia Izadi-Pruneyre (1) , Michael Nilges (1)

1 Bioinformatique structurale - Structural Bioinformatics
2 C3BI - Centre de Bioinformatique, Biostatistique et Biologie Intégrative
3 Plateforme technologique de RMN biologique - Biological NMR Technological Platform

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.

Domaines: Biologie structurale [q-bio.BM]; Bio-informatique [q-bio.QM]; Biophysique; Biochimie, Biologie Moléculaire; Sciences du Vivant [q-bio]

Benjamin Bardiaux, Florence Cordier, Sébastien Brier, Aracelys López-Castilla, Nadia Izadi-Pruneyre, et al.. Dynamics of a type 2 secretion system pseudopilus unraveled by complementary approaches. Journal of Biomolecular NMR, 2019, 73 (6-7), pp.293-303. ⟨10.1007/s10858-019-00246-4⟩. ⟨hal-02990168⟩