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Figure 5
Time-resolved chemotaxis signalling sample preparation using E. coli minicells. (a) Atlas view (145× magnification) of a representative EM lacey carbon grid prepared using the photolysis setup integrating the PORTO laser and Vitrobot. The sample loaded on the grid consists of purified minicells and DMNB-photocaged serine. The grid was plunge-frozen with a delay of ∼150 ms following light irradiation. Grid squares within the highlighted region (red dashed outline) were selected for cryoET data collection. (b) Representative grid overview (8700× magnification) used to assess minicell distribution and ice thickness. (c) Tomographic slice from the region highlighted by the dashed rectangle in (b). The yellow arrow points to a chemotaxis array. (d) Enlarged view of a minicell from (c), showing identifiable structural features including the outer membrane (OM), inner membrane (IM), chemotaxis array (CA) and flagellar motor (FM). (e) Template-matching results (green spheres) obtained using emClarity, showing matched hexagonal patterns of the chemotaxis array overlaid on the tomogram region corresponding to (d). (f) Preliminary subtomogram averaged maps of the tri-CSU complex at ∼20 Å resolution for the laser-off and laser-on datasets.

IUCrJ
Volume 13| Part 4| July 2026| Pages 395-408
ISSN: 2052-2525
https://doi.org/10.1107/S2052252526005324