Abstract
E1 enzymes activate ubiquitin-like proteins and transfer them to cognate E2 enzymes. Atg7, a noncanonical E1, activates two ubiquitin-like proteins, Atg8 and Atg12, and plays a crucial role in autophagy. Here, we report crystal structures of full-length Atg7 and its C-terminal domain bound to Atg8 and MgATP, as well as a solution structure of Atg8 bound to the extreme C-terminal domain (ECTD) of Atg7. The unique N-terminal domain (NTD) of Atg7 is responsible for Atg3 (E2) binding, whereas its C-terminal domain is comprised of a homodimeric adenylation domain (AD) and ECTD. The structural and biochemical data demonstrate that Atg8 is initially recognized by the C-terminal tail of ECTD and is then transferred to an AD, where the Atg8 C terminus is attacked by the catalytic cysteine to form a thioester bond. Atg8 is then transferred via a trans mechanism to the Atg3 bound to the NTD of the opposite protomer within a dimer.
Copyright © 2011 Elsevier Inc. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphate / metabolism
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Autophagy-Related Protein 7
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Autophagy-Related Protein 8 Family
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Autophagy-Related Proteins
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Binding Sites
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Crystallography, X-Ray
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Enzyme Activation
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Microtubule-Associated Proteins / chemistry*
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Microtubule-Associated Proteins / genetics
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Microtubule-Associated Proteins / metabolism
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Models, Molecular
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Multienzyme Complexes
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Mutation
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Protein Conformation
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Protein Interaction Domains and Motifs
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Protein Interaction Mapping
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Protein Multimerization
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae Proteins / chemistry*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Structure-Activity Relationship
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Time Factors
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Ubiquitin-Conjugating Enzymes / chemistry
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Ubiquitin-Conjugating Enzymes / metabolism
Substances
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ATG7 protein, S cerevisiae
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ATG8 protein, S cerevisiae
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Autophagy-Related Protein 8 Family
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Autophagy-Related Proteins
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Microtubule-Associated Proteins
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Multienzyme Complexes
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Adenosine Triphosphate
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Ubiquitin-Conjugating Enzymes
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Autophagy-Related Protein 7
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ATG3 protein, S cerevisiae
Associated data
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PDB/2LI5
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PDB/3VH1
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PDB/3VH2
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PDB/3VH3
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PDB/3VH4