6fyh

Disulfide between ubiquitin G76C and the E3 HECT ligase Huwe1

spinqualitylabelsall models 6fyh, resolution 2.91Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6fyh is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.906Å Ligands: SO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Ubiquitin (Ub) ligases (E3s) catalyze the attachment of Ub chains to target proteins and thereby regulate a wide array of signal transduction pathways in eukaryotes. In HECT-type E3s, Ub first forms a thioester intermediate with a strictly conserved Cys in the C-lobe of the HECT domain and is then ligated via an isopeptide bond to a Lys residue in the substrate or a preceding Ub in a poly-Ub chain. To date, many key aspects of HECT-mediated Ub transfer have remained elusive. Here, we provide structural and functional insights into the catalytic mechanism of the HECT-type ligase Huwe1 and compare it to the unrelated, K63-specific Smurf2 E3, a member of the Nedd4 family. We found that the Huwe1 HECT domain, in contrast to Nedd4-family E3s, prioritizes K6- and K48-poly-Ub chains and does not interact with Ub in a non-covalent manner. Despite these mechanistic differences, we demonstrate that the architecture of the C-lobe~Ub intermediate is conserved between Huwe1 and Smurf2 and involves a reorientation of the very C-terminal residues. Moreover, in Nedd4 E3s and Huwe1 the individual sequence composition of the Huwe1 C-terminal tail modulates ubiquitination activity, without affecting thioester formation. In sum, our data suggest that catalysis of HECT ligases hold common features, such as the beta-sheet augmentation that primes the enzymes for ligation, and variable elements, such as the sequence of the HECT C-terminal tail, that fine-tune ubiquitination activity and may aid in determining Ub chain specificity by positioning the substrate or acceptor Ub. beta-Sheet Augmentation Is a Conserved Mechanism of Priming HECT E3 Ligases for Ubiquitin Ligation.,Jackl M, Stollmaier C, Strohaker T, Hyz K, Maspero E, Polo S, Wiesner S J Mol Biol. 2018 Jun 28. pii: S0022-2836(18)30705-8. doi:, 10.1016/j.jmb.2018.06.044. PMID:29964046 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ubiquitin protein ligase 3D structures 3D structures of ubiquitin

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