6d4p
Ube2D1 in complex with ubiquitin variant Ubv.D1.1
Structural highlights
FunctionUB2D1_HUMAN Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-48'-linked polyubiquitination. Mediates the selective degradation of short-lived and abnormal proteins. Functions in the E6/E6-AP-induced ubiquitination of p53/TP53. Mediates ubiquitination of PEX5 and auto-ubiquitination of STUB1, TRAF6 and TRIM63/MURF1. Ubiquitinates STUB1-associated HSP90AB1 in vitro. Lacks inherent specificity for any particular lysine residue of ubiquitin. Essential for viral activation of IRF3. Mediates polyubiquitination of CYP3A4.[1] [2] [3] [4] [5] Publication Abstract from PubMedUbiquitin-conjugating E2 enzymes are central to the ubiquitination cascade and have been implicated in cancer and other diseases. Despite strong interest in developing specific E2 inhibitors, the shallow and exposed active site has proven recalcitrant to targeting with reversible small-molecule inhibitors. Here, we used phage display to generate highly potent and selective ubiquitin variants (UbVs) that target the E2 backside, which is located opposite to the active site. A UbV targeting Ube2D1 did not affect charging but greatly attenuated chain elongation. Likewise, a UbV targeting the E2 variant Ube2V1 did not interfere with the charging of its partner E2 enzyme but inhibited formation of di-ubiquitin. In contrast, a UbV that bound to the backside of Ube2G1 impeded the generation of thioester-linked ubiquitin to the active site cysteine of Ube2G1 by the E1 enzyme. Crystal structures of UbVs in complex with three E2 proteins revealed distinctive molecular interactions in each case, but they also highlighted a common backside pocket that the UbVs utilized for enhanced affinity and specificity. These findings validate the E2 backside as a target for inhibition and provide structural insights to aid inhibitor design and screening efforts. Structural and Functional Analysis of Ubiquitin-based inhibitors that Target the Backsides of E2 Enzymes.,Garg P, Ceccarelli DF, Keszei AF, Kourinov I, Sicheri F, Sidhu SS J Mol Biol. 2019 Oct 18. pii: S0022-2836(18)30280-8. doi:, 10.1016/j.jmb.2019.09.024. PMID:31634471[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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