Structure of the Ubiquitin Hydrolase UCH-L3 Complexed with a Suicide Substrate

Journal Article · Tue Mar 24 04:00:00 EDT 2009 · J. Biol. Chem.

DOI:https://doi.org/10.1074/jbc.M410770200· OSTI ID:1008479

Misaghi, S; Galardy, P J; Meester, W J; Ovaa, H; Ploegh, H L; Gaudet, R ^[1]

---

1. Harvard

Ubiquitin C-terminal hydrolases (UCHs) comprise a family of small ubiquitin-specific proteases of uncertain function. Although no cellular substrates have been identified for UCHs, their highly tissue-specific expression patterns and the association of UCH-L1 mutations with human disease strongly suggest a critical role. The structure of the yeast UCH Yuh1-ubiquitin aldehyde complex identified an active site crossover loop predicted to limit the size of suitable substrates. We report the 1.45 {angstrom} resolution crystal structure of human UCH-L3 in complex with the inhibitor ubiquitin vinylmethylester, an inhibitor that forms a covalent adduct with the active site cysteine of ubiquitin-specific proteases. This structure confirms the predicted mechanism of the inhibitor and allows the direct comparison of a UCH family enzyme in the free and ligand-bound state. We also show the efficient hydrolysis by human UCH-L3 of a 13-residue peptide in isopeptide linkage with ubiquitin, consistent with considerable flexibility in UCH substrate size. We propose a model for the catalytic cycle of UCH family members which accounts for the hydrolysis of larger ubiquitin conjugates.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1008479
• Journal Information: J. Biol. Chem., Journal Name: J. Biol. Chem. Journal Issue: (2) ; 01, 2005 Vol. 280; ISSN JBCHA3; ISSN 0021-9258
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
ADDUCTS
ALDEHYDES
CRYSTAL STRUCTURE
CYSTEINE
DISEASES
ENZYMES
FLEXIBILITY
HYDROLASES
HYDROLYSIS
MUTATIONS
PEPTIDES
RESOLUTION
SUBSTRATES
YEASTS