Crystallization and preliminary X-ray crystallographic study of human Hikeshi, a new nuclear transport receptor for Hsp70.

Hikeshi is a new nuclear transport receptor that plays an important role in the nuclear import of Hsp70 heat-shock proteins under thermal stress. Wild-type human Hikeshi and its Phe97Ala mutant were overproduced and purified using an Escherichia coli expression system. The purified proteins were crystallized using the hanging-drop vapour-diffusion technique. Wild-type crystals grew in space group C2221, with unit-cell parameters a = 61.1, b = 137.8, c = 97.9 Å, α = 90.0, β = 90.0, γ = 90.0°. Phe97Ala mutant crystals were obtained in space group P32, with unit-cell parameters a = 85.7, b = 85.7, c = 69.1 Å, α = 90.0, β = 90.0, γ = 120.0°. These crystals diffracted to 1.8 and 2.5 Å resolution, respectively. This study is the first to yield structural insight into this highly unusual fourth import receptor after importins, NTF2 and TAP.