Table 1.

Microscopy and image reconstruction data

SampleParticle imagesaResolutionb (Å)EM Data Bank identifier
80S-P1 (both binding sites)5,25621d5284
80S-P1 (propeller tip only)1,132185286
80S-P1 (2-fold only)1,814185285
  • a Total number of images; divide by two for the number of image pairs (focal pairs). These images were extracted from seven focal-pair micrographs, where the first image in the pair was taken closer to focus and the second image was taken farther from focus. The pixel size for the reconstructions was 1.83 Å. For the orientation and origin determination, images were corrected only for phase-flipping effects of the CTF. For the final, published reconstruction, images were fully deconvoluted for CTF effects and a signal-decay correction was also applied (see Materials and Methods section).

  • b Determined by the point at which the Fourier shell correlation value reaches 0.5. For the Fourier shell correlation test, images were corrected only for the phase-flipping effects of the CTF.

  • c The difference in the number of particles used is attributable to classification of particles that matched best with a model containing an Fab on the propeller tip (2,110) against a model without an Fab bound (see Materials and Methods). The other reconstruction (10,160) was from iterative model-based orientation and origin refinement against all 135S particles in the data set. In the latter, all particles that matched well were included.

  • d Lower-resolution versions of the 12-Å 135S-P1 and 13-Å 80S-P1 maps were computed so that the bound Fabs could be seen more easily.