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1z3h
From Proteopedia
The exportin Cse1 in its cargo-free, cytoplasmic state
Overview
Cse1 mediates nuclear export of importin alpha, the nuclear localization signal (NLS) import adaptor. We report the 3.1 A resolution structure of cargo-free Cse1, representing this HEAT repeat protein in its cytosolic state. Cse1 is compact, consisting of N- and C-terminal arches that interact to form a ring. Comparison with the structure of cargo-bound Cse1 shows a major conformational change leading to opening of the structure upon cargo binding. The largest structural changes occur within a hinge region centered at HEAT repeat 8. This repeat contains a conserved insertion that connects the RanGTP and importin alpha contact sites and that is essential for binding. In the cargo-free state, the RanGTP binding sites are occluded and the importin alpha sites are distorted. Mutations that destabilize the N- to C-terminal interaction uncouple importin alpha and Ran binding, suggesting that the closed conformation prevents association with importin alpha.
About this Structure
1Z3H is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
The structure of the nuclear export receptor Cse1 in its cytosolic state reveals a closed conformation incompatible with cargo binding., Cook A, Fernandez E, Lindner D, Ebert J, Schlenstedt G, Conti E, Mol Cell. 2005 Apr 29;18(3):355-67. PMID:15866177 Page seeded by OCA on Sat May 3 17:08:19 2008
