Abstract
E1 enzymes facilitate conjugation of ubiquitin and ubiquitin-like proteins through adenylation, thioester transfer within E1, and thioester transfer from E1 to E2 conjugating proteins. Structures of human heterodimeric Sae1/Sae2-Mg.ATP and Sae1/Sae2-SUMO-1-Mg.ATP complexes were determined at 2.2 and 2.75 A resolution, respectively. Despite the presence of Mg.ATP, the Sae1/Sae2-SUMO-1-Mg.ATP structure reveals a substrate complex insomuch as the SUMO C-terminus remains unmodified within the adenylation site and 35 A from the catalytic cysteine, suggesting that additional changes within the adenylation site may be required to facilitate chemistry prior to adenylation and thioester transfer. A mechanism for E2 recruitment to E1 is suggested by biochemical and genetic data, each of which supports a direct role for the E1 C-terminal ubiquitin-like domain for E2 recruitment during conjugation.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Triphosphate / chemistry
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Adenosine Triphosphate / metabolism
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Amino Acid Sequence
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Catalytic Domain
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Crystallography, X-Ray
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Dimerization
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Enzyme Activation
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Humans
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In Vitro Techniques
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Models, Molecular
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Molecular Sequence Data
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Multiprotein Complexes
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NEDD8 Protein
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Protein Structure, Tertiary
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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SUMO-1 Protein / chemistry*
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SUMO-1 Protein / genetics
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SUMO-1 Protein / metabolism
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Sequence Homology, Amino Acid
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Ubiquitin-Activating Enzymes / chemistry*
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Ubiquitin-Activating Enzymes / genetics
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Ubiquitin-Activating Enzymes / metabolism
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Ubiquitins / metabolism
Substances
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Multiprotein Complexes
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NEDD8 Protein
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NEDD8 protein, human
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Recombinant Proteins
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SUMO-1 Protein
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UBA2 protein, human
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Ubiquitins
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Adenosine Triphosphate
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SAE1 protein, human
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Ubiquitin-Activating Enzymes