Abstract
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.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Crystallography, X-Ray / methods
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Endosomal Sorting Complexes Required for Transport / chemistry*
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Endosomal Sorting Complexes Required for Transport / genetics
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Endosomal Sorting Complexes Required for Transport / metabolism*
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Protein Binding
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Protein Structure, Tertiary
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Saccharomyces cerevisiae Proteins / chemistry*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Ubiquitin / metabolism*
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Ubiquitin-Protein Ligase Complexes / chemistry*
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Ubiquitin-Protein Ligase Complexes / genetics
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Ubiquitin-Protein Ligase Complexes / metabolism*
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Ubiquitination
Substances
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Endosomal Sorting Complexes Required for Transport
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Saccharomyces cerevisiae Proteins
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Ubiquitin
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Ubiquitin-Protein Ligase Complexes
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RSP5 protein, S cerevisiae