Fig. 1: Engineering of homogeneous C. jejuni minicells enabled determination of an in situ structure of a flagellar motor by single-particle analysis electron cryo-microscopy.
a, Schematic of the flagellar motor6. Proton flux through the stator complexes drives rotation of the C-ring, MS-ring, rod and hook/filament. In C. jejuni and other Campylobacterota, a basal disk and periplasmic scaffold have evolved that scaffold a wider ring of additional stator complexes thought to increase motor torque17. IM/OM, inner/outer membrane. b, Wildtype C. jejuni cells used in previous studies17 typically provide 1 flagellar motor per field of view (arrowhead) as compared with c, many motors per field of view in our minicell strain (arrowheads), greatly increasing throughput and reducing sample thickness for higher-quality electron micrograph acquisition. Note that curvature of minicells is comparable to wildtype cells. The 51781 raw micrographs are available from EMPIAR90 (https://doi.org/10.6019/EMPIAR-11580). d, Periplasmic and cytoplasmic features are evident in single-particle analysis 2D classes of manually picked motors. e, Cross-section through an isosurface rendering of a C17 whole-motor 3D reconstruction (deposited as EMD-16723). f, Map from e segmented and exploded along the z axis to highlight component substructures.
