Fig. 2.

Class averages obtained with images of the same specimen areas recorded on film and on imaging plates at different magnifications and using different binnings. (a–e) 20S proteasome recorded first on film at 52 000× with a binning of 3 (a), then on IPs at 30 000× without binning (b), then on IPs at 67 000× with a binning of 2 (c), then on IPs at 110 000× with a binning of 3 (d) and finally on film again at 52 000× with a binning of 3 (e). The side length of the individual class averages is 38.8 nm (a and e), 48 nm (b), 43 nm (c) and 39.3 nm (d). (f–j) Tf–TfR complex recorded first on film at 52 000× with a binning of 3 (f), then on IPs at 30 000× without binning (g), then on IPs at 67 000× with a binning of 2 (h), then on IPs at 110 000× with a binning of 3 (i), and finally on film again at 52 000× with a binning of 3 (j). The side length of the individual class averages is 25.9 nm (f and j), 32 nm (g), 28.7 nm (h) and 26.2 nm (i). All the class averages in panels (a)–(e) and panels (f)–(j) contain the same particles. The particles appear bright on a dark background.