Structure and function of a HECT domain ubiquitin-binding site.

Hyung Cheol Kim, Alanna M Steffen, Michael L Oldham, Jue Chen, Jon M Huibregtse

Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA.

EMBO reports 2011 Apr

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The Rsp5 ubiquitin ligase contains a non-covalent binding site for ubiquitin within the amino-terminal lobe (N-lobe) of the HECT domain, and the X-ray crystal structure of the HECT-ubiquitin complex has been determined. Hydrophobic patch residues of ubiquitin (L8, I44, V70) were crucial for interaction with Rsp5, and amino-acid alterations at the Rsp5-binding interface resulted in defects in polyubiquitination. Our results support a model in which the N-lobe-binding site acts to localize and orient the distal end of the ubiquitin chain to promote conjugation of the next ubiquitin molecule.

Citation

Hyung Cheol Kim, Alanna M Steffen, Michael L Oldham, Jue Chen, Jon M Huibregtse. Structure and function of a HECT domain ubiquitin-binding site. EMBO reports. 2011 Apr;12(4):334-41