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

TY - JOUR

T1 - Refined Cryo-EM Structure of the T4 Tail Tube

T2 - Exploring the Lowest Dose Limit

AU - Zheng, Weili

AU - Wang, Fengbin

AU - Taylor, Nicholas M I

AU - Guerrero-Ferreira, Ricardo C

AU - Leiman, Petr G

AU - Egelman, Edward H

N1 - Copyright © 2017 Elsevier Ltd. All rights reserved.

PY - 2017/9/5

Y1 - 2017/9/5

N2 - 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/Å2using 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.

AB - 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/Å2using 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.

KW - Bacteriophage T4/chemistry

KW - Cryoelectron Microscopy/methods

KW - Models, Molecular

KW - Molecular Conformation

KW - Software

U2 - 10.1016/j.str.2017.06.017

DO - 10.1016/j.str.2017.06.017

M3 - Journal article

C2 - 28757144

SN - 0969-2126

VL - 25

SP - 1436-1441.e2

JO - Structure

JF - Structure

IS - 9

ER -