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Publication Abstract from PubMed

Several systems, including contractile tail bacteriophages, the type VI secretion system and R-type pyocins, use a multiprotein tubular apparatus to attach to and penetrate host cell membranes. This macromolecular machine resembles a stretched, coiled spring (or sheath) wound around a rigid tube with a spike-shaped protein at its tip. A baseplate structure, which is arguably the most complex part of this assembly, relays the contraction signal to the sheath. Here we present the atomic structure of the approximately 6-megadalton bacteriophage T4 baseplate in its pre- and post-host attachment states and explain the events that lead to sheath contraction in atomic detail. We establish the identity and function of a minimal set of components that is conserved in all contractile injection systems and show that the triggering mechanism is universally conserved.

Structure of the T4 baseplate and its function in triggering sheath contraction.,Taylor NM, Prokhorov NS, Guerrero-Ferreira RC, Shneider MM, Browning C, Goldie KN, Stahlberg H, Leiman PG Nature. 2016 May 18;533(7603):346-52. doi: 10.1038/nature17971. PMID:27193680^[3]

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