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. 2016 Feb 23;110(4):798–809. doi: 10.1016/j.bpj.2016.01.016

Figure 2.

Figure 2

Representative cryo-EM data and data-quality indicators for integrin samples. (A) Representative gallery of particles picked from unprocessed micrographs of samples with integrin. These particles represent random projections of all four conformations with defined Euler angles with respect to the 3D reconstructions. The conformations are color coded as in Fig. 1, B and C: upright (blue), bent (red), first intermediate (green), and second intermediate (yellow). The width of the boxes is 44 nm (applies to entire figure). (B) Surface representations of models of the corresponding integrin conformations in matching orientations (using the defined Euler angles) of images in (A). Blue, α-subunit; red, β-subunit; green, talin; yellow, nanodisc. (C) Representative gallery of particles picked from unprocessed micrographs of samples with integrin, talin F3, RGD peptide, and nanodisc. As in (A), these particles represent all four conformations. (D) Surface representations of models of the corresponding integrin conformations in matching orientations (using the defined Euler angles) of images in (C). (E and F) Five representative class averages (top row) drawn from the angular classification (see H) and corresponding reconstruction projections (bottom row) for the upright (E) and bent (F) conformations generated from the same data set that was used to generate (C), but after iterative multireference classification. (G) Fourier shell correlation curves for the 3D reconstructions of integrin conformations in the presence of nanodiscs, talin head domain, and RGD peptide. The 0.5 cutoff criterion indicates resolutions between 4.5 and 3 nm. The color code of the curves corresponds to that used in Fig. 1, B and C. (H) Distribution of integrin particles in the upright conformation on the sample support grid with an angular sampling of 15°. The number of particles corresponding to a particular orientation is proportional to the brightness of the spots (see bar). The distribution indicates that the particles are nearly randomly distributed. The distributions of Euler angles for the other data sets display similarly uniform coverage. To see this figure in color, go online.