Trans-Binding Mechanism of Ubiquitin-like Protein Activation Revealed by a UBA5-UFM1 Complex
Walaa Oweis,
Prasanth Padala,
Fouad Hassouna,
Einav Cohen-Kfir,
Dalton R. Gibbs,
Emily A. Todd,
Christopher E. Berndsen,
Reuven Wiener
Affiliations
Walaa Oweis
Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
Prasanth Padala
Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
Fouad Hassouna
Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
Einav Cohen-Kfir
Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
Dalton R. Gibbs
Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, VA 22807, USA
Emily A. Todd
Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, VA 22807, USA
Christopher E. Berndsen
Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, VA 22807, USA
Reuven Wiener
Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
Modification of proteins by ubiquitin or ubiquitin-like proteins (UBLs) is a critical cellular process implicated in a variety of cellular states and outcomes. A prerequisite for target protein modification by a UBL is the activation of the latter by activating enzymes (E1s). Here, we present the crystal structure of the non-canonical homodimeric E1, UBA5, in complex with its cognate UBL, UFM1, and supporting biochemical experiments. We find that UBA5 binds to UFM1 via a trans-binding mechanism in which UFM1 interacts with distinct sites in both subunits of the UBA5 dimer. This binding mechanism requires a region C-terminal to the adenylation domain that brings UFM1 to the active site of the adjacent UBA5 subunit. We also find that transfer of UFM1 from UBA5 to the E2, UFC1, occurs via a trans mechanism, thereby requiring a homodimer of UBA5. These findings explicitly elucidate the role of UBA5 dimerization in UFM1 activation.
