1u4a
Solution structure of human SUMO-3 C47S
Structural highlights
FunctionSUMO3_HUMAN Ubiquitin-like protein which can be covalently attached to target lysines either as a monomer or as a lysine-linked polymer. Does not seem to be involved in protein degradation and may function as an antagonist of ubiquitin in the degradation process. Plays a role in a number of cellular processes such as nuclear transport, DNA replication and repair, mitosis and signal transduction. Covalent attachment to its substrates requires prior activation by the E1 complex SAE1-SAE2 and linkage to the E2 enzyme UBE2I, and can be promoted by an E3 ligase such as PIAS1-4, RANBP2 or CBX4.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSmall ubiquitin-related modifier SUMO-3 is a member of a growing family of ubiquitin-like proteins (Ubls). So far, four isoforms of SUMO have been identified in humans. It is generally known that SUMO modification regulates protein localization and activity. Previous structure and function studies have been mainly focused on SUMO-1. The sequence of SUMO-3 is 46% identical with that of SUMO-1; nevertheless, functional heterogeneity has been found between the two homologues. Here we report the solution structure of SUMO-3 C47S (residues 14-92) featuring the beta-beta-alpha-beta-beta-alpha-beta ubiquitin fold. Structural comparison shows that SUMO-3 C47S resembles ubiquitin more than SUMO-1. On the helix-sheet interface, a strong hydrophobic interaction contributes to formation of the globular and compact fold. A Gly-Gly motif at the C-terminal tail, extending away from the core structure, is accessible to enzymes and substrates. In vivo, SUMO modification proceeds via a multistep pathway, and Ubc9 plays an indispensable role as the SUMO conjugating enzyme (E2) in this process. To develop a better understanding of SUMO-3 conjugation, the Ubc9 binding surface on SUMO-3 C47S has been detected by chemical shift perturbation using NMR spectroscopy. The binding site mainly resides on the hydrophilic side of the beta-sheet. Negatively charged and hydrophobic residues of this region are highly or moderately conserved among SUMO family members. Notably, the negatively charged surface of SUMO-3 C47S is highly complementary in its electrostatic potentials and hydrophobicity to the positively charged surface of Ubc9. This work indicates dissimilarities between SUMO-3 and SUMO-1 in tertiary structure and provides insight into the specific interactions of SUMO-3 with its modifying enzyme. Solution structure of human SUMO-3 C47S and its binding surface for Ubc9.,Ding H, Xu Y, Chen Q, Dai H, Tang Y, Wu J, Shi Y Biochemistry. 2005 Mar 1;44(8):2790-9. PMID:15723523[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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