Cryo-ET of purified Rickettsia parkeri ompBSTOP::tn bacteria (1.9 A, UW-Madison K3)

Aligned cryo-electron tilt series and reconstructed tomograms of purified Rickettsia parkeri ompBSTOP::tn (ompB-null transposon-insertion mutant, strain Portsmouth) bacteria spotted onto holey-carbon grids and plunge-frozen without permeabilization or fixation. Imaged on a Titan Krios (300 kV) with a K3 detector and Gatan energy filter at the UW-Madison MCCET, ~1.9 A pixel size, dose-symmetric tilt scheme with 3 degree increment and ~100 e/A2 total dose. Tomograms were reconstructed in RELION 5 with marker-free AreTomo2 alignment and CTF estimation (Fourier-space reconstruction), binned to 10 A voxel size. The paracrystalline S-layer is absent in the ompB mutant, in contrast to wild-type bacteria.