1U4A

Solution structure of human SUMO-3 C47S

Summary for 1U4A

• Entry DOI: 10.2210/pdb1u4a/pdb
• Related: 1A5R
• Descriptor: Ubiquitin-like protein SMT3A (1 entity in total)
• Functional Keywords: beta beta alpha beta beta alpha beta fold, protein binding
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P55854
• Total number of polymer chains: 1
• Total formula weight: 10118.25

Authors

Ding, H.,Xu, Y.,Dai, H.,Tang, Y.,Wu, J.,Shi, Y. (deposition date: 2004-07-23, release date: 2005-03-08, Last modification date: 2024-05-29)

Primary citation

Ding, H.,Xu, Y.,Chen, Q.,Dai, H.,Tang, Y.,Wu, J.,Shi, Y.
Solution Structure of Human SUMO-3 C47S and Its Binding Surface for Ubc9
Biochemistry, 44:2790-2799, 2005

PubMed Abstract: Small 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.

PubMed: 15723523
DOI: 10.1021/bi0477586

Experimental method

SOLUTION NMR