Structural highlights
FunctionUBA1_SCHPO Activates ubiquitin by first adenylating its C-terminal glycine residue with ATP, and thereafter linking this residue to the side chain of a cysteine residue in E1, yielding an ubiquitin-E1 thioester and free AMP. Publication Abstract from PubMedUbiquitin (Ub) E1 initiates the Ub conjugation cascade by activating and transferring Ub to tens of different E2s. How Ub E1 cooperates with E2s that differ substantially in their predicted E1-interacting residues is unknown. Here, we report the structure of S. pombe Uba1 in complex with Ubc15, a Ub E2 with intrinsically low E1-E2 Ub thioester transfer activity. The structure reveals a distinct Ubc15 binding mode that substantially alters the network of interactions at the E1-E2 interface compared to the only other available Ub E1-E2 structure. Structure-function analysis reveals that the intrinsically low activity of Ubc15 largely results from the presence of an acidic residue at its N-terminal region. Notably, Ub E2 N termini are serine/threonine rich in many other Ub E2s, leading us to hypothesize that phosphorylation of these sites may serve as a novel negative regulatory mechanism of Ub E2 activity, which we demonstrate biochemically and in cell-based assays. S. pombe Uba1-Ubc15 Structure Reveals a Novel Regulatory Mechanism of Ubiquitin E2 Activity.,Lv Z, Rickman KA, Yuan L, Williams K, Selvam SP, Woosley AN, Howe PH, Ogretmen B, Smogorzewska A, Olsen SK Mol Cell. 2017 Feb 16;65(4):699-714.e6. doi: 10.1016/j.molcel.2017.01.008. Epub, 2017 Feb 2. PMID:28162934[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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