1xd3
From Proteopedia
Crystal structure of UCHL3-UbVME complex
Overview
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.
About this Structure
1XD3 is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structure of the ubiquitin hydrolase UCH-L3 complexed with a suicide substrate., Misaghi S, Galardy PJ, Meester WJ, Ovaa H, Ploegh HL, Gaudet R, J Biol Chem. 2005 Jan 14;280(2):1512-20. Epub 2004 Nov 5. PMID:15531586 Page seeded by OCA on Sat May 3 14:52:37 2008
