Primary Citation of Related Structures:   1XD3
PubMed Abstract: 
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 ...
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 A 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.
Related Citations: 
Chemistry-based functional proteomics reveals novel members of the deubiquitinating enzyme family Borodovsky, A., Ovaa, H., Kolli, N., Gan-Erdene, T., Wilkinson, K.D., Ploegh, H.L., Kessler, B.M. (2002) Chem Biol 9: 1149
A novel active site-directed probe specific for deubiquitinating enzymes reveals proteasome association of USP14 Borodovsky, A., Kessler, B.M., Casagrande, R., Overkleeft, H.S., Wilkinson, K.D., Ploegh, H.L. (2001) EMBO J 20: 5187
Crystal structure of a deubiquitinating enzyme (human UCH-L3) at 1.8 A resolution Johnston, S.C., Larsen, C.N., Cook, W.J., Wilkinson, K.D., Hill, C.P. (1997) EMBO J 16: 3787
Structural basis for the specificity of ubiquitin C-terminal hydrolases Johnston, S.C., Riddle, S.M., Cohen, R.E., Hill, C.P. (1999) EMBO J 18: 3877
Organizational Affiliation: 
Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.