1r4m
From Proteopedia
APPBP1-UBA3-NEDD8, an E1-ubiquitin-like protein complex
Structural highlights
Function[ULA1_HUMAN] Regulatory subunit of the dimeric UBA3-NAE1 E1 enzyme. E1 activates NEDD8 by first adenylating its C-terminal glycine residue with ATP, thereafter linking this residue to the side chain of the catalytic cysteine, yielding a NEDD8-UBA3 thioester and free AMP. E1 finally transfers NEDD8 to the catalytic cysteine of UBE2M. Necessary for cell cycle progression through the S-M checkpoint. Overexpression of NAE1 causes apoptosis through deregulation of NEDD8 conjugation.[1] [2] [3] [NEDD8_HUMAN] Ubiquitin-like protein which plays an important role in cell cycle control and embryogenesis. Covalent attachment to its substrates requires prior activation by the E1 complex UBE1C-APPBP1 and linkage to the E2 enzyme UBE2M. Attachment of NEDD8 to cullins activates their associated E3 ubiquitin ligase activity, and thus promotes polyubiquitination and proteasomal degradation of cyclins and other regulatory proteins.[4] [5] [6] [UBA3_HUMAN] Catalytic subunit of the dimeric UBA3-NAE1 E1 enzyme. E1 activates NEDD8 by first adenylating its C-terminal glycine residue with ATP, thereafter linking this residue to the side chain of the catalytic cysteine, yielding a NEDD8-UBA3 thioester and free AMP. E1 finally transfers NEDD8 to the catalytic cysteine of UBE2M. Down-regulates steroid receptor activity. Necessary for cell cycle progression.[7] [8] [9] 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 PubMedE1 enzymes initiate ubiquitin-like protein (ubl) transfer cascades by catalyzing adenylation of the ubl's C terminus. An E1's selectivity for its cognate ubl is essential because the E1 subsequently coordinates the ubl with its correct downstream pathway. We report here the structure of the 120 kDa quaternary complex between human APPBP1-UBA3, a heterodimeric E1, its ubl NEDD8, and ATP. The E1 selectively recruits NEDD8 through a bipartite interface, involving a domain common to all ubl activating enzymes including bacterial ancestors, and also eukaryotic E1-specific sequences. By modeling ubiquitin into the NEDD8 binding site and performing mutational analysis, we identify a single conserved arginine in APPBP1-UBA3 that acts as a selectivity gate, preventing misactivation of ubiquitin by NEDD8's E1. NEDD8 residues that interact with E1 correspond to residues in ubiquitin important for binding the proteasome and other ubiquitin-interacting proteins, suggesting that the conjugation and recognition machineries have coevolved for each specific ubl. The structure of the APPBP1-UBA3-NEDD8-ATP complex reveals the basis for selective ubiquitin-like protein activation by an E1.,Walden H, Podgorski MS, Huang DT, Miller DW, Howard RJ, Minor DL Jr, Holton JM, Schulman BA Mol Cell. 2003 Dec;12(6):1427-37. PMID:14690597[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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