3ceg
Crystal structure of the UBC domain of baculoviral IAP repeat-containing protein 6
Structural highlights
FunctionBIRC6_HUMAN Anti-apoptotic protein which can regulate cell death by controlling caspases and by acting as an E3 ubiquitin-protein ligase. Has an unusual ubiquitin conjugation system in that it could combine in a single polypeptide, ubiquitin conjugating (E2) with ubiquitin ligase (E3) activity, forming a chimeric E2/E3 ubiquitin ligase. Its tragets include CASP9 and DIABLO/SMAC. Acts as an inhibitor of CASP3, CASP7 and CASP9. Important regulator for the final stages of cytokinesis. Crucial for normal vesicle targeting to the site of abscission, but also for the integrity of the midbody and the midbody ring, and its striking ubiquitin modification.[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 PubMedHere we describe a systematic structure-function analysis of the human ubiquitin (Ub) E2 conjugating proteins, consisting of the determination of 15 new high-resolution three-dimensional structures of E2 catalytic domains, and autoubiquitylation assays for 26 Ub-loading E2s screened against a panel of nine different HECT (homologous to E6-AP carboxyl terminus) E3 ligase domains. Integration of our structural and biochemical data revealed several E2 surface properties associated with Ub chain building activity; (1) net positive or neutral E2 charge, (2) an "acidic trough" located near the catalytic Cys, surrounded by an extensive basic region, and (3) similarity to the previously described HECT binding signature in UBE2L3 (UbcH7). Mass spectrometry was used to characterize the autoubiquitylation products of a number of functional E2-HECT pairs, and demonstrated that HECT domains from different subfamilies catalyze the formation of very different types of Ub chains, largely independent of the E2 in the reaction. Our data set represents the first comprehensive analysis of E2-HECT E3 interactions, and thus provides a framework for better understanding the molecular mechanisms of ubiquitylation. A human ubiquitin conjugating enzyme (E2)-HECT E3 ligase structure-function screen.,Sheng Y, Hong JH, Doherty R, Srikumar T, Shloush J, Avvakumov GV, Walker JR, Xue S, Neculai D, Wan JW, Kim SK, Arrowsmith CH, Raught B, Dhe-Paganon S Mol Cell Proteomics. 2012 Aug;11(8):329-41. Epub 2012 Apr 10. PMID:22496338[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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