Priming and polymerization of a bacterial contractile tail structure. 1" 2" 17"

Abdelrahim Zoued (1) , Eric Durand (1) , Yannick R Brunet (1) , Silvia Spinelli (2) , Badreddine Douzi (2) , Mathilde Guzzo (3) , Nicolas Flaugnatti (1) , Pierre Legrand (4) , Laure Journet (1) , Rémi Fronzes (5) , Tam Mignot (3) , Christian Cambillau (2) , E. Cascales (1)

1 LISM - Laboratoire d'ingénierie des systèmes macromoléculaires
2 AFMB - Architecture et fonction des macromolécules biologiques
3 LCB - Laboratoire de chimie bactérienne
4 SSOLEIL - Synchrotron SOLEIL
5 European Institute of Chemistry and Biology

Contractile tails are composed of an inner tube wrapped by an outer sheath assembled in an extended, metastable conformation that stores mechanical energy necessary for its contraction. Contraction is used to propel the rigid inner tube towards target cells for DNA or toxin delivery. Although recent studies have revealed the structure of the Type VI secretion system contractile sheath, the mechanisms by which its polymerization is controlled and coordinated with inner tube assembly remain unsolved. In this study, we report that the starfish-like TssA dodecameric complex interacts with tube and sheath components. Fluorescence microscopy experiments revealed that TssA binds first to the T6SS membrane core complex and then initiates tail polymerization. TssA remains at the tip of the growing structure and incorporates new tube and sheath blocks. Based on these results, we propose that TssA primes and coordinates tail tube and sheath biogenesis.

Keywords: Crystallography, X-Ray; Escherichia coli/*chemistry/ultrastructure; Escherichia coli Proteins/*chemistry/*metabolism/ultrastructure; Microscopy, Electron; *Polymerization; Protein Structure, Tertiary; Type VI Secretion Systems/chemistry/metabolism/ultrastructure

Keywords: Microscopy, Fluorescence; Models, Molecular

Domains: Life Sciences [q-bio]; Life Sciences [q-bio]; Biochemistry, Molecular Biology; Life Sciences [q-bio]; Biochemistry, Molecular Biology; Biochemistry [q-bio.BM]; Life Sciences [q-bio]; Biochemistry, Molecular Biology; Molecular biology; Life Sciences [q-bio]; Biochemistry, Molecular Biology; Structural Biology [q-bio.BM]; Life Sciences [q-bio]; Cellular Biology; Life Sciences [q-bio]; Microbiology and Parasitology

Abdelrahim Zoued, Eric Durand, Yannick R Brunet, Silvia Spinelli, Badreddine Douzi, et al.. Priming and polymerization of a bacterial contractile tail structure. 1" 2" 17". Nature, 2016, 531 (7592), pp.59 - 63. ⟨10.1038/nature17182⟩. ⟨hal-01778575⟩