1. Action of a minimal contractile bactericidal nanomachine
- Author
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Ge, Peng, Scholl, Dean, Prokhorov, Nikolai S, Avaylon, Jaycob, Shneider, Mikhail M, Browning, Christopher, Buth, Sergey A, Plattner, Michel, Chakraborty, Urmi, Ding, Ke, Leiman, Petr G, Miller, Jeff F, and Zhou, Z Hong
- Subjects
Bacteriophage T4 ,Cryoelectron Microscopy ,Crystallography ,X-Ray ,Genes ,Bacterial ,Models ,Molecular ,Protein Subunits ,Pseudomonas aeruginosa ,Pyocins ,Substrate Specificity ,Type VI Secretion Systems ,General Science & Technology - Abstract
R-type bacteriocins are minimal contractile nanomachines that hold promise as precision antibiotics1-4. Each bactericidal complex uses a collar to bridge a hollow tube with a contractile sheath loaded in a metastable state by a baseplate scaffold1,2. Fine-tuning of such nucleic acid-free protein machines for precision medicine calls for an atomic description of the entire complex and contraction mechanism, which is not available from baseplate structures of the (DNA-containing) T4 bacteriophage5. Here we report the atomic model of the complete R2 pyocin in its pre-contraction and post-contraction states, each containing 384 subunits of 11 unique atomic models of 10 gene products. Comparison of these structures suggests the following sequence of events during pyocin contraction: tail fibres trigger lateral dissociation of baseplate triplexes; the dissociation then initiates a cascade of events leading to sheath contraction; and this contraction converts chemical energy into mechanical force to drive the iron-tipped tube across the bacterial cell surface, killing the bacterium.
- Published
- 2020