Amino-terminal Dimerization, NRDP1-Rhodanese Interaction, and Inhibited Catalytic Domain Conformation of the Ubiquitin-specific Protease 8 (USP8).
Avvakumov, G.V., Walker, J.R., Xue, S., Finerty Jr., P.J., Mackenzie, F., Newman, E.M., Dhe-Paganon, S.(2006) J Biol Chem 281: 38061-38070
- PubMed: 17035239 
- DOI: https://doi.org/10.1074/jbc.M606704200
- Primary Citation of Related Structures:  
2A9U, 2FZP, 2GFO, 2GWF - PubMed Abstract: 
Ubiquitin-specific protease 8 (USP8) hydrolyzes mono and polyubiquitylated targets such as epidermal growth factor receptors and is involved in clathrin-mediated internalization. In 1182 residues, USP8 contains multiple domains, including coiled-coil, rhodanese, and catalytic domains. We report the first high-resolution crystal structures of these domains and discuss their implications for USP8 function. The amino-terminal domain is a homodimer with a novel fold. It is composed of two five-helix bundles, where the first helices are swapped, and carboxyl-terminal helices are extended in an antiparallel fashion. The structure of the rhodanese domain, determined in complex with the E3 ligase NRDP1, reveals the canonical rhodanese fold but with a distorted primordial active site. The USP8 recognition domain of NRDP1 has a novel protein fold that interacts with a conserved peptide loop of the rhodanese domain. A consensus sequence of this loop is found in other NRDP1 targets, suggesting a common mode of interaction. The structure of the carboxyl-terminal catalytic domain of USP8 exhibits the conserved tripartite architecture but shows unique traits. Notably, the active site, including the ubiquitin binding pocket, is in a closed conformation, incompatible with substrate binding. The presence of a zinc ribbon subdomain near the ubiquitin binding site further suggests a polyubiquitin-specific binding site and a mechanism for substrate induced conformational changes.
Organizational Affiliation: 
Structural Genomics Consortium and the Department of Physiology, University of Toronto, Toronto, Ontario M5G 1L5, Canada.