Structure determination of the small ubiquitin-related modifier SUMO-1.Bayer, P., Arndt, A., Metzger, S., Mahajan, R., Melchior, F., Jaenicke, R., Becker, J.
(1998) J.Mol.Biol. 280: 275-286
- PubMed: 9654451
- DOI: 10.1006/jmbi.1998.1839
- PubMed Abstract:
- A Small Ubiquitin-Related Polypeptide Involved in Targeting Rangap1 to Nuclear Pore Complex Protein Ranbp2
Mahajan, R.,Delphin, C.,Guan, T.,Gerace, L.,Melchior, F.
(1997) Cell 88: 97
- A Novel Ubiquitin-Like Modification Modulates the Partitioning of the Ran-Gtpase-Activating Protein Rangap1 between the Cytosol and the Nuclear Pore Complex
Matunis, M.J.,Coutavas, E.,Blobel, G.
(1996) J.Cell Biol. 135: 1457
- Preferential Modification of Nuclear Proteins by a Novel Ubiquitin-Like Molecule
Kamitani, T.,Nguyen, H.P.,Yeh, E.T.
(1997) J.Biol.Chem. 272: 14001
The recently discovered small ubiquitin-related modifier SUMO-1 belongs to the growing family of ubiquitin-related proteins involved in postranslational protein modification. Unlike ubiquitin, SUMO-1 does not appear to target proteins for degradation ...
The recently discovered small ubiquitin-related modifier SUMO-1 belongs to the growing family of ubiquitin-related proteins involved in postranslational protein modification. Unlike ubiquitin, SUMO-1 does not appear to target proteins for degradation but seems to be involved in the modulation of protein-protein interactions. Independent studies demonstrate an essential function of SUMO-1 in the regulation of nucleo-cytoplasmic transport, and suggest a role in cell-cycle regulation and apoptosis. Here, we present the first three-dimensional structure of SUMO-1 solved by NMR. Although having only 18% amino acid sequence identity with ubiquitin, the overall structure closely resembles that of ubiquitin, featuring the betabetaalphabetabetaalphabeta fold of the ubiquitin protein family. In addition, the position of the two C-terminal Gly residues required for isopeptide bond formation is conserved between ubiquitin and SUMO-1. The most prominent feature of SUMO-1 is a long and highly flexible N terminus, which protrudes from the core of the protein and which is absent in ubiquitin. Furthermore, ubiquitin Lys48, required to generate ubiquitin polymers, is substituted in SUMO-1 by Gln69 at the same position, which provides an explanation of why SUMO-1 has not been observed to form polymers. Moreover, the hydrophobic core of SUMO-1 and ubiquitin is maintained by conserved hydrophobic residues, whereas the overall charge topology of SUMO-1 and ubiquitin differs significantly, suggesting specific modifying enzymes and target proteins for both proteins.
Abteilung Physikalische Biochemie, Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany.