Architectural nucleoporins Nup157/170 and Nup133 are structurally related and descend from a second ancestral element.
Publication Type:Journal Article
Source:J Biol Chem, Volume 284, Issue 41, p.28442-52 (2009)
Keywords:Amino Acid Sequence, Crystallography, X-Ray, Evolution, Molecular, Humans, Minor Histocompatibility Antigens, Models, Molecular, Molecular Sequence Data, Multiprotein Complexes, Nuclear Pore, Nuclear Pore Complex Proteins, Protein Structure, Secondary, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Alignment, Sequence Homology, Amino Acid
<p>The nuclear pore complex (NPC) constitutes one of the largest protein assemblies in the eukaryotic cell and forms the exclusive gateway to the nucleus. The stable, approximately 15-20-MDa scaffold ring of the NPC is built from two multiprotein complexes arranged around a central 8-fold axis. Here we present crystal structures of two large architectural units, yNup170(979-1502) and hNup107(658-925) x hNup133(517-1156), each a constituent of one of the two multiprotein complexes. Conservation of domain arrangement and of tertiary structure suggests that Nup157/170 and Nup133 derived from a common ancestor. Together with the previously established ancestral coatomer element (ACE1), these two elements constitute the major alpha-helical building blocks of the NPC scaffold and define its branched, lattice-like architecture, similar to vesicle coats like COPII. We hypothesize that the extant NPC evolved early during eukaryotic evolution from a rudimentary structure composed of several identical copies of a few ancestral elements, later diversified and specified by gene duplication.</p>