Structural highlights
Function[TUBE_BPT4] Structural component of the bacteriophage tail which consists of a contractile sheath, a tube and a baseplate. The central cylindrical segment of the tail consists of a rigid tube, composed of multiple copies of gp19, surrounded by the outer contractile sheath assembled from gp18 subunits. During infection, contraction of the sheath drives the central tube through the host outer membrane, creating a channel for DNA ejection from the capsid into the host cell.[1] Publication Abstract from PubMedThe bacteriophage T4 contractile tail (containing a tube and sheath) was the first biological assembly reconstructed in three dimensions by electron microscopy at a resolution of approximately 35 A in 1968. A single-particle reconstruction of the T4 baseplate was able to generate a 4.1 A resolution map for the first two rings of the tube using the overall baseplate for alignment. We have now reconstructed the T4 tail tube at a resolution of 3.4 A, more than a 1,000-fold increase in information content for the tube from 1968. We have used legacy software (Spider) to show that we can do better than the typical 2/3 Nyquist frequency. A reasonable map can be generated with only 1.5 electrons/A2 using the higher dose images for alignment, but increasing the dose results in a better map, consistent with other reports that electron dose does not represent the main limitation on resolution in cryo-electron microscopy. Refined Cryo-EM Structure of the T4 Tail Tube: Exploring the Lowest Dose Limit.,Zheng W, Wang F, Taylor NMI, Guerrero-Ferreira RC, Leiman PG, Egelman EH Structure. 2017 Jul 10. pii: S0969-2126(17)30213-7. doi:, 10.1016/j.str.2017.06.017. PMID:28757144[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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This page was last modified 05:53, 17 August 2017.