title: Structural and biochemical characterization of the Importin-beta.Ran.GTP.RanBD1 complex.
abstract: Here we present the crystal structure of Importin-beta(1-462).Ran.GTP.RanBD1DeltaN as solved by molecular replacement. HPLC dissociation measurements on this complex show, that the N-terminus of RanBD may be involved in the release of the hydrolysis- and dissociation-block of Ran by Transportin/Importin-beta. We could identify a pair of amino acids which - upon mutation - weaken the interaction between Ran and Importin-beta specifically to allow dissociation without RanBD. These findings support the hypothesis that a ternary complex of Importin-beta.Ran.GTP.RanBD exists in the final step of the export of Importin-beta from the nucleus and that interaction of the N-terminus of RanBD with Ran plays a crucial role in disassembly of this complex.
authors.affiliation: Max-Planck-Institute for Molecular Physiology, Department Structural Biology, Otto-Hahn-Str. 11, D-44227 Dortmund, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Sarić
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhao
authors.forename: Carolin
authors.initials: C
authors.lastname: Körner
authors.forename: Christine
authors.initials: C
authors.lastname: Nowak
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kuhlmann
authors.forename: Ingrid R
authors.initials: IR
authors.lastname: Vetter
mesh_terms: D018360:Crystallography, X-Ray; D006160:Guanosine Triphosphate / Q000737:chemistry*; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry*; D009687:Nuclear Proteins / Q000737:chemistry*; D011487:Protein Conformation; D028961:beta Karyopherins / Q000737:chemistry*; D020931:ran GTP-Binding Protein / Q000737:chemistry*
chemical_list: D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D028961:beta Karyopherins; C091775:ran-binding protein 1; D006160:Guanosine Triphosphate; D020931:ran GTP-Binding Protein