FIG. 2.

(a) Selected projection images (recorded at tilt angles of 0°, 35°, and 70°) from a 250-nm-thick section obtained from cells overproducing Tsr. (b and c) Slices from an electron tomogram constructed by using a series of tilted images from −70° to 70° at tilt intervals of 0.5°. The slice in panel b is from a region closer to the surface of the section, while the slice in panel c is from an interior region that is not accessible to the protein A-gold particles. Bars, 0.17 μm (b and c). (d) Computed Fourier transform from a region in the x-y slice of the tomogram, showing Thon rings at a resolution of 15 Å⁻¹ in the x-y plane (indicated by the arrow). The region of the slice used to calculate the transform contains a flagellar filament whose helical structure is responsible for producing the elongated spots in the transform in the horizontal direction. (e) Transform in the x-z plane from a similar-size region, showing the expected missing wedge due to the absence of data between tilt angles of 70° and 90° and Thon rings at a resolution of ∼22 Å⁻¹ (indicated by the arrow). The edge of the transform in panels d and e is at 13 Å⁻¹.