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Publication Abstract from PubMed

R-type bacteriocins are minimal contractile nanomachines that hold promise as precision antibiotics(1-4). Each bactericidal complex uses a collar to bridge a hollow tube with a contractile sheath loaded in a metastable state by a baseplate scaffold(1,2). 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 bacteriophage(5). 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.

Action of a minimal contractile bactericidal nanomachine.,Ge P, Scholl D, Prokhorov NS, Avaylon J, Shneider MM, Browning C, Buth SA, Plattner M, Chakraborty U, Ding K, Leiman PG, Miller JF, Zhou ZH Nature. 2020 Apr;580(7805):658-662. doi: 10.1038/s41586-020-2186-z. Epub 2020 Apr, 15. PMID:32350467^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.