3ny2
From Proteopedia
Structure of the ubr-box of UBR2 ubiquitin ligase
Structural highlights
Function[UBR2_HUMAN] E3 ubiquitin-protein ligase which is a component of the N-end rule pathway. Recognizes and binds to proteins bearing specific N-terminal residues that are destabilizing according to the N-end rule, leading to their ubiquitination and subsequent degradation. Plays a critical role in chromatin inactivation and chromosome-wide transcriptional silencing during meiosis via ubiquitination of histone H2A. Binds leucine and is a negative regulator of the leucine-mTOR signaling pathway, thereby controlling cell growth.[1] [2] [3] 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 N-end rule links the half-life of a protein to the identity of its N-terminal residue. Destabilizing N-terminal residues are recognized by E3 ubiquitin ligases, termed N-recognins. A conserved structural domain called the UBR box is responsible for their specificity. Here we report the crystal structures of the UBR boxes of the human N-recognins UBR1 and UBR2, alone and in complex with an N-end rule peptide, Arg-Ile-Phe-Ser. These structures show that the UBR box adopts a previously undescribed fold stabilized through the binding of three zinc ions to form a binding pocket for type 1 N-degrons. NMR experiments reveal a preference for N-terminal arginine. Peptide binding is abrogated by N-terminal acetylation of the peptide or loss of the positive charge of the N-terminal residue. These results rationalize and refine the empirical rules for the classification of type 1 N-degrons. We also confirm that a missense mutation in UBR1 that is responsible for Johanson-Blizzard syndrome leads to UBR box unfolding and loss of function. Structural basis of substrate recognition and specificity in the N-end rule pathway.,Matta-Camacho E, Kozlov G, Li FF, Gehring K Nat Struct Mol Biol. 2010 Oct;17(10):1182-7. Epub 2010 Sep 12. PMID:20835242[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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