Fig. 2

Structure of human importin α3 bound to RCC1. a A representative structure of the human importin α3:RCC1 complex with RCC1 (ribbon diagram) and importin α3 (solvent surface) colored in green and gray, respectively. RCC1 hinge residues (23–27) are colored in red. b Eight-fold non-crystallographic symmetry averaged 2Fo − Fc electron density map of the RCC1 NLS displayed at 1σ above background. The density (in blue) is overlaid to residues 4–24 of the final refined model (in green). c SAXS analysis of the importin α3:RCC1 complex. Experimental scattering data (shown in black) obtained by merging scattering data at 3.5, 5.0, and 7.5 mg ml⁻¹ (top panel) and corresponding distance distribution function P(r) (bottom panel). Scattering profile and P(r) function calculated from the average of the eight importin α3:RCC1 complexes observed crystallographically are shown in red. d. Ab initio SAXS reconstruction of the importin α3:RCC1 complex calculated from merged scattering intensities at 3.5, 5.0, and 7.5 mg ml⁻¹. Overlaid to the SAXS envelope is a composite of all complexes in the triclinic unit cell