6dc6
Crystal structure of human ubiquitin activating enzyme E1 (Uba1) in complex with ubiquitin
Structural highlights
DiseaseUBA1_HUMAN X-linked distal arthrogryposis multiplex congenita. The disease is caused by mutations affecting the gene represented in this entry. FunctionUBA1_HUMAN Catalyzes the first step in ubiquitin conjugation to mark cellular proteins for degradation through the ubiquitin-proteasome system. 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 a ubiquitin-E1 thioester and free AMP. Essential for the formation of radiation-induced foci, timely DNA repair and for response to replication stress. Promotes the recruitment of TP53BP1 and BRCA1 at DNA damage sites.[1] Publication Abstract from PubMedUbiquitin (Ub) signaling plays a key regulatory role in nearly every aspect of eukaryotic biology and is initiated by E1 enzymes that activate and transfer Ub to E2 Ub-conjugating enzymes. Despite Ub E1's fundamental importance to the cell and its attractiveness as a target for therapeutic intervention in cancer and other diseases, its only available structural information is derived from yeast orthologs of human ubiquitin-like modifier-activating enzyme 1 (hUBA1). To illuminate structural differences between yeast and hUBA1 structures that might be exploited for the development of small-molecule therapeutics, we determined the first crystal structure of a hUBA1/Ub complex. Using structural analysis, molecular modeling, and biochemical analysis, we demonstrate that hUBA1 shares a conserved overall structure and mechanism with previously characterized yeast orthologs, but displays subtle structural differences, particularly within the active site. Computational analysis revealed four potential ligand-binding hotspots on the surface of hUBA1 that might serve as targets to inhibit hUBA1 at the level of Ub activation or E2 recruitment or that might potentially be used in approaches such as protein-targeting chimeric molecules (PROTACs). Taken together, our work enhances our understanding of the hUBA1 mechanism, provides an improved framework for the development of small-molecule inhibitors of UBA1, and serves as a stepping stone for structural studies that involve the enzymes of the human Ub system at the level of both E1 and E2. Crystal structure of a human ubiquitin E1-ubiquitin complex reveals conserved functional elements essential for activity.,Lv Z, Williams KM, Yuan L, Atkison JH, Olsen SK J Biol Chem. 2018 Oct 2. pii: RA118.003975. doi: 10.1074/jbc.RA118.003975. PMID:30279270[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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