Molecular basis for bre5 cofactor recognition by the ubp3 deubiquitylating enzyme.

Yeast Ubp3 and its co-factor Bre5 form a deubiquitylation complex to regulate protein transport between the endoplasmic reticulum and Golgi compartments of the cell. A novel N-terminal domain of the Ubp3 catalytic subunit forms a complex with the NTF2-like domain of the Bre5 regulatory subunit. Here, we report the X-ray ...
crystal structure of an Ubp3-Bre5 complex and show that it forms a symmetric hetero-tetrameric complex in which the Bre5 NTF2-like domain dimer interacts with two L-shaped beta-strand-turn-alpha-helix motifs of Ubp3. The Ubp3 N-terminal domain binds within a hydrophobic cavity on the surface of the Bre5 NTF2-like domain subunit with conserved residues within both proteins interacting predominantly through antiparallel beta-sheet hydrogen bonds and van der Waals contacts. Structure-based mutagenesis and functional studies confirm the significance of the observed interactions for Ubp3-Bre5 association in vitro and Ubp3 function in vivo. Comparison of the structure to other protein complexes with NTF2-like domains shows that the Ubp3-Bre5 interface is novel. Together, these studies provide new insights into Ubp3 recognition by Bre5 and into protein recognition by NTF2-like domains.
Mesh Terms:
Amino Acid Sequence, Binding Sites, Carrier Proteins, Coenzymes, Endopeptidases, Models, Molecular, Molecular Sequence Data, Mutagenesis, Site-Directed, Protein Binding, Protein Processing, Post-Translational, Protein Structure, Tertiary, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Ubiquitin
J. Mol. Biol.
Date: Sep. 07, 2007
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