3h8k | pdb_00003h8k
Crystal structure of Ube2g2 complxed with the G2BR domain of gp78 at 1.8-A resolution
Structural highlights
FunctionUB2G2_HUMAN Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-48'-linked polyubiquitination. Involved in endoplasmic reticulum-associated degradation (ERAD).[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 PubMedThe activity of RING finger ubiquitin ligases (E3) is dependent on their ability to facilitate transfer of ubiquitin from ubiquitin-conjugating enzymes (E2) to substrates. The G2BR domain within the E3 gp78 binds selectively and with high affinity to the E2 Ube2g2. Through structural and functional analyses, we determine that this occurs on a region of Ube2g2 distinct from binding sites for ubiquitin-activating enzyme (E1) and RING fingers. Binding to the G2BR results in conformational changes in Ube2g2 that affect ubiquitin loading. The Ube2g2:G2BR interaction also causes an approximately 50-fold increase in affinity between the E2 and RING finger. This results in markedly increased ubiquitylation by Ube2g2 and the gp78 RING finger. The significance of this G2BR effect is underscored by enhanced ubiquitylation observed when Ube2g2 is paired with other RING finger E3s. These findings uncover a mechanism whereby allosteric effects on an E2 enhance E2-RING finger interactions and, consequently, ubiquitylation. Allosteric activation of E2-RING finger-mediated ubiquitylation by a structurally defined specific E2-binding region of gp78.,Das R, Mariano J, Tsai YC, Kalathur RC, Kostova Z, Li J, Tarasov SG, McFeeters RL, Altieri AS, Ji X, Byrd RA, Weissman AM Mol Cell. 2009 Jun 26;34(6):674-85. PMID:19560420[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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