Figure 6.

Binding properties of snurportin 1 deletion mutants. Immobilized full-length snurportin 1 (lanes 2 and 3) or deletion mutants (lanes 4–11) were tested for binding of (A) CRM1 and (B) importin β from total E. coli lysates. Where indicated, 1.5 μM RanQ69L GTP had also been added. Analysis was as in Fig. 2. Note that deletion of the 26 NH₂-terminal residues of snurportin 1 abolished binding to CRM1. Deletion of >74 residues from the COOH terminus of snurportin 1 also resulted in the loss of the CRM1 interaction. All fragments that contained the IBB domain (residues 25–65) bound importin β.