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

Weili Zheng, Fengbin Wang, Nicholas M.I. Taylor, Ricardo C. Guerrero-Ferreira, Petr G. Leiman, Edward H. Egelman

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1436-1441.e2
JournalStructure
Volume25
Issue number9
DOIs
StatePublished - Sep 5 2017

Keywords

  • R-type pyocin
  • bacteriophage
  • bacteriophage tail
  • contractile injection system
  • helical filaments

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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