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E2-binding surface on Uba3 β-grasp domain undergoes a conformational transition. Proteins 2012 Oct;80(10):2482-7 PMID: 22821745

Abstract

The covalent attachment of ubiquitin (Ub) and ubiquitin-like (Ubl) proteins to various eukaryotic targets plays critical roles in regulating numerous cellular processes. E1-activating enzymes are critical, because they catalyze activation of their cognate Ub/Ubl protein and are responsible for its transfer to the correct E2-conjugating enzyme(s). The activating enzyme for neural-precursor-cell-expressed developmentally downregulated 8 (NEDD8) is a heterodimer composed of APPBP1 and Uba3 subunits. The carboxyl terminal ubiquitin-like β-grasp domain of human Uba3 (Uba3-βGD) has been suggested as a key E2-binding site defining E2 specificity. In crystal structures of free E1 and the NEDD8-E1 complex, the E2-binding surface on the domain was missing from the electron density. However, when complexed with various E2s, this missing segment adopts a kinked α-helix. Here, we demonstrate that Uba3-βGD is an independently folded domain in solution and that residues involved in E2 binding are absent from the NMR spectrum, indicating that the E2-binding surface on Uba3-βGD interconverts between multiple conformations, analogous to a similar conformational transition observed in the E2-binding surface of SUMO E1. These results suggest that access to multiple conformational substates is an important feature of the E1-E2 interaction.

Author List

Elgin ES, Sökmen N, Peterson FC, Volkman BF, Dağ C, Haas AL

Authors

Francis C. Peterson PhD Professor in the Biochemistry department at Medical College of Wisconsin
Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Animals
Binding Sites
Cattle
Humans
Mice
Models, Molecular
Molecular Sequence Data
Nuclear Magnetic Resonance, Biomolecular
Protein Binding
Protein Conformation
Protein Structure, Tertiary
Rats
Sequence Alignment
Ubiquitin-Activating Enzymes



View this publication's entry at the Pubmed website PMID: 22821745
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