Conformational heterogeneity of karyopherin beta2 is segmental.

ABSTRACT: Karyopherinbeta2 (Kap beta2) or transportin imports numerous RNA binding proteins into the nucleus. Kap beta2 binds substrates in the cytoplasm and targets them through the nuclear pore complex, where RanGTP dissociates them in the nucleus. Here we report the 3.0 A crystal structure of unliganded Kap beta2, which consists of a superhelix of 20 HEAT repeats. Together with previously reported structures of NLS and Ran complexes, this structure provides understanding of conformational heterogeneity that accompanies ligand binding. The Kap beta2 superhelix is divided into three major segments. Two of them (HEAT repeats 9-13 and 14-18), which constitute the substrate binding site, are rigid elements that rotate relative to each other about a flexible hinge. The third (HEAT repeats 1-8), which c

SUBMITTER: Cansizoglu AE 

PROVIDER: S-EPMC3437625 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature