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Biochemistry, Biophysics, and Structural Biology

2013

Amino Acid

Articles 1 - 1 of 1

Full-Text Articles in Life Sciences

Mechanism Of Ubiquitin Ligation And Lysine Prioritization By A Hect E3, Hari B. Kamadurai, Yu Qiu, Alan Deng, Joseph S. Harrison, Chris Macdonald, Marcelo Actis, Patrick Rodrigues, Darcie J. Miller, Judith Souphron, Steven M. Lewis, Igor Kurinov, Naoaki Fujii, Michal Hammel, Robert Piper, Brian Kuhlman, Brenda A. Schulman Aug 2013

Mechanism Of Ubiquitin Ligation And Lysine Prioritization By A Hect E3, Hari B. Kamadurai, Yu Qiu, Alan Deng, Joseph S. Harrison, Chris Macdonald, Marcelo Actis, Patrick Rodrigues, Darcie J. Miller, Judith Souphron, Steven M. Lewis, Igor Kurinov, Naoaki Fujii, Michal Hammel, Robert Piper, Brian Kuhlman, Brenda A. Schulman

College of the Pacific Faculty Articles

Ubiquitination by HECT E3 enzymes regulates myriad processes, including tumor suppression, transcription, protein trafficking, and degradation. HECT E3s use a two-step mechanism to ligate ubiquitin to target proteins. The first step is guided by interactions between the catalytic HECT domain and the E2∼ubiquitin intermediate, which promote formation of a transient, thioester-bonded HECT∼ubiquitin intermediate. Here we report that the second step of ligation is mediated by a distinct catalytic architecture established by both the HECT E3 and its covalently linked ubiquitin. The structure of a chemically trapped proxy for an E3∼ubiquitin-substrate intermediate reveals three-way interactions between ubiquitin and the bilobal HECT …