Refined Cryo-EM Structure of the T4 Tail Tube: Exploring the Lowest Dose Limit

Academic Article


  • The 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 ∼35 Å in 1968. A single-particle reconstruction of the T4 baseplate was able to generate a 4.1 Å 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 Å, 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/Å2 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.
  • Authors

    Published In

  • Folding & design  Journal
  • Digital Object Identifier (doi)

    Author List

  • Zheng W; Wang F; Taylor NMI; Guerrero-Ferreira RC; Leiman PG; Egelman EH
  • Start Page

  • 1436
  • End Page

  • 1441.e2
  • Volume

  • 25
  • Issue

  • 9