Figure 2—figure supplement 2. | The export receptor Crm1 forms a dimer to promote nuclear export of HIV RNA

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The export receptor Crm1 forms a dimer to promote nuclear export of HIV RNA

Figure 2—figure supplement 2.

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University of California, San Francisco, United States
Figure 2—figure supplement 2.
Download figureOpen in new tabFigure 2—figure supplement 2. Comparison of fitting murine Crm1 or human Crm1 crystal structures in the EM reconstruction.

(A) Two murine Crm1-RanGTP (PDB 3NC0) monomers individually fit well (Correlation (R) = 0.7526 or 0.7393) into two bowl-like densities from the reconstruction of Crm1-RanGTP bound to Rev-RRE. The final fit places residues different between murine and human Crm1 (gold) to potentially form an interface between two Crm1 monomers. (B) From the fit of murine Crm1, we inferred that the same residues might form a crystal contact between Crm1 monomers in the crystal structure of human Crm1 bound to Snurportin-1 (PDB 3GB8) and this, indeed, was observed. The fit of the human Crm1 dimer structure is shown (R = 0.8227). Although the crystal structures of murine Crm1 either have two Crm1 molecules in the asymmetric unit or other dimers in the unit cell, these alternate dimers use different crystal contacts to build the unit cell and do not have the same conformation as the human Crm1 dimer (data not shown). (C) A hybrid model of the Crm1 dimer bound to RanGTP. The human Crm1 interface was used to orient two copies of murine Crm1 bound to RanGTP by aligning murine Crm1 with the human Crm1 interface, which shows little deviation between Cα atoms. The final model fits well (R = 0.9047) into the EM map and was used to search for Rev-RRE density shown in Figure 3.