2eke

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spinqualitylabelsall models 2eke, resolution 1.9Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of a SUMO-binding-motif mimic bound to Smt3p-Ubc9p: conservation of a noncovalent Ubiquitin-like protein-E2 complex as a platform for selective interactions within a SUMO pathway

Overview

The SUMO ubiquitin-like proteins play regulatory roles in cell division, transcription, DNA repair, and protein subcellular localization., Paralleling other ubiquitin-like proteins, SUMO proteins are, proteolytically processed to maturity, conjugated to targets by E1-E2-E3, cascades, and subsequently recognized by specific downstream effectors, containing a SUMO-binding motif (SBM). SUMO and its E2 from the budding, yeast Saccharomyces cerevisiae, Smt3p and Ubc9p, are encoded by essential, genes. Here we describe the 1.9 A resolution crystal structure of a, non-covalent Smt3p-Ubc9p complex. Unexpectedly, a heterologous portion of, the crystallized complex derived from the expression construct mimics an, SBM, and binds Smt3p in a manner resembling SBM binding to human SUMO, family members. In the complex, Smt3p binds a surface distal from Ubc9's, catalytic cysteine. The structure implies that a single molecule of Smt3p, cannot bind concurrently to both the non-covalent binding site and the, catalytic cysteine of a single Ubc9p molecule. However, formation of, higher-order complexes can occur, where a single Smt3p covalently linked, to one Ubc9p's catalytic cysteine also binds non-covalently to another, molecule of Ubc9p. Comparison with other structures from the SUMO pathway, suggests that formation of the non-covalent Smt3p-Ubc9p complex occurs, mutually exclusively with many other Smt3p and Ubc9p interactions in the, conjugation cascade. By contrast, high-resolution insights into how, Smt3p-Ubc9p can also interact with downstream recognition machineries come, from contacts with the SBM mimic. Interestingly, the overall architecture, of the Smt3p-Ubc9p complex is strikingly similar to recent structures from, the ubiquitin pathway. The results imply that non-covalent ubiquitin-like, protein-E2 complexes are conserved platforms, which function as parts of, larger assemblies involved in many protein post-translational regulatory, pathways.

About this Structure

2EKE is a Protein complex structure of sequences from Saccharomyces cerevisiae. Active as Ubiquitin--protein ligase, with EC number 6.3.2.19 Full crystallographic information is available from OCA.

Reference

Structure of a SUMO-binding-motif Mimic Bound to Smt3p-Ubc9p: Conservation of a Non-covalent Ubiquitin-like Protein-E2 Complex as a Platform for Selective Interactions within a SUMO Pathway., Duda DM, van Waardenburg RC, Borg LA, McGarity S, Nourse A, Waddell MB, Bjornsti MA, Schulman BA, J Mol Biol. 2007 Jun 8;369(3):619-30. Epub 2007 Apr 10. PMID:17475278

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