title: The tail structure of bacteriophage T4 and its mechanism of contraction.
abstract: Bacteriophage T4 and related viruses have a contractile tail that serves as an efficient mechanical device for infecting bacteria. A three-dimensional cryo-EM reconstruction of the mature T4 tail assembly at 15-A resolution shows the hexagonal dome-shaped baseplate, the extended contractile sheath, the long tail fibers attached to the baseplate and the collar formed by six whiskers that interact with the long tail fibers. Comparison with the structure of the contracted tail shows that tail contraction is associated with a substantial rearrangement of the domains within the sheath protein and results in shortening of the sheath to about one-third of its original length. During contraction, the tail tube extends beneath the baseplate by about one-half of its total length and rotates by 345 degrees , allowing it to cross the host's periplasmic space.
authors.affiliation: Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, Indiana 47907-2054, USA.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Kostyuchenko
authors.forename: Paul R
authors.initials: PR
authors.lastname: Chipman
authors.forename: Petr G
authors.initials: PG
authors.lastname: Leiman
authors.forename: Fumio
authors.initials: F
authors.lastname: Arisaka
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Mesyanzhinov
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rossmann
mesh_terms: D017122:Bacteriophage T4 / Q000737:chemistry* / Q000502:physiology* / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D008958:Models, Molecular; D011487:Protein Conformation; D013329:Structure-Activity Relationship