Purification, crystallization and preliminary X-ray analysis of a Nup107-Nup133 heterodimeric nucleoporin complex.

The nuclear pore complex (NPC), the sole gateway of traffic between the nucleus and the cytoplasm, is built up from multiple copies of about 30 proteins collectively termed nucleoporins (nups). Nups are organized into distinct subcomplexes. Nup107 and Nup133 are members of the essential Nup107-160 subcomplex, a component of the central NPC architecture. A dimeric complex of the C-terminal domains of human Nup107 and Nup133 was expressed from a bicistronic vector in Escherichia coli, purified and crystallized in two different crystal forms. Crystals grown in the presence of 18-22% PEG 3350 belong to space group P2(1)2(1)2(1) and diffracted to 2.9 A. Native and seleno-L-methionine-derivative crystals grown in the presence of 1.1 M sodium malonate belong to space group C2 and diffracted to 2.55 and 2.9 A, respectively. Structure determination of this complex will give the first insights into the protein-protein interactions within a core module of the NPC.