Nucleoplasmin-like domain of FKBP39 from Drosophila melanogaster forms a tetramer with partly disordered tentacle-like C-terminal segments

作者：Kozlowska Malgorzata; Tarczewska Aneta; Jakob Michal; Bystranowska Dominika; Taube Michal; Kozak Maciej; Czarnocki Cieciura Mariusz; Dziembowski Andrzej; Orlowski Marek; Tkocz Katarzyna; Ozyhar Andrzej^*

来源：Scientific Reports, 2017, 7(1): 40405.

DOI：10.1038/srep40405

Nucleoplasmins are a nuclear chaperone family defined by the presence of a highly conserved N-terminal core domain. X-ray crystallographic studies of isolated nucleoplasmin core domains revealed a beta-propeller structure consisting of a set of five monomers that together form a stable pentamer. Recent studies on isolated N-terminal domains from Drosophila 39-kDa FK506-binding protein (FKBP39) and from other chromatin-associated proteins showed analogous, nucleoplasminlike (NPL) pentameric structures. Here, we report that the NPL domain of the full-length FKBP39 does not form pentameric complexes. Multi-angle light scattering (MALS) and sedimentation equilibrium ultracentrifugation (SE AUC) analyses of the molecular mass of the full-length protein indicated that FKBP39 forms homotetrameric complexes. Molecular models reconstructed from small-angle X-ray scattering (SAXS) revealed that the NPL domain forms a stable, tetrameric core and that FK506-binding domains are linked to it by intrinsically disordered, flexible chains that form tentacle-like segments. Analyses of full-length FKBP39 and its isolated NPL domain suggested that the distal regions of the polypeptide chain influence and determine the quaternary conformation of the nucleoplasminlike protein. These results provide new insights regarding the conserved structure of nucleoplasmin core domains and provide a potential explanation for the importance of the tetrameric structural organization of full-length nucleoplasmins.

• 出版日期2017-1-11