Figure 1.

Electron microscopy of representative gold particles and their protein coat. Gold particles (A, 22 nm; B, 26 nm; and C, 36 nm) uncoated (first row) and coated with NP or BSA (second row) were visualized in the electron microscope by negative staining. The third and fourth rows are examples of NP- and BSA-coated gold particles that were incubated first with importin α (NP + α and BSA + α) and then with importin β (NP + α + β and BSA + α + β). The last row shows examples of NP- and BSA-coated gold particles that were incubated with importin α and β and then immunogold labeled with an anti-importin β antibody directly conjugated with 8-nm gold particles.