Ran in Nucleocytoplasmic Transport - Ras Superfamily Small G Proteins: Biology and Mechanisms 2 - page 110

a

b

C

C

Fig. 6.3 Conformational changes in karyopherin structures associated with RanGTP binding. (a)
The helicoid of the importin- nuclear export factor, Cse1, undergoes a considerable conforma-

tional change between the isolated molecules ( red , PDB accession code 1Z3H, Cook et al. 2005 )
and when bound to RanGTP and yeast importin-

α

( black , PDB accession code 1WA5, Matsuura
and Stewart 2004 ). (b) Although yeast CRM1 (Xpo1) shows less change in the helicoid pitch
between the isolated molecule ( pink / red , PDB accession code 3VYC, Saito and Matsuura 2013 )
and when bound to RanGTP and cargo ( gray / black , PDB accession code 3M1I, Koyama and
Matsuura 2010 ), there is a major change in the position of the C-terminal helix that, in the
RanGTP:cargo complex ( red ), takes up a position immediately below the NES-binding site,
whereas in the isolated molecule it binds near the N-terminus ( black )

α