title: Structural basis of Atg8 activation by a homodimeric E1, Atg7.
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.
authors: Institute of Microbial Chemistry, Tokyo, Tokyo 141-0021, Japan. nn@bikaken.or.jp
authors: Nobuo N
authors: NN
authors: Noda
authors: Kenji
authors: K
authors: Satoo
authors: Yuko
authors: Y
authors: Fujioka
authors: Hiroyuki
authors: H
authors: Kumeta
authors: Kenji
authors: K
authors: Ogura
authors: Hitoshi
authors: H
authors: Nakatogawa
authors: Yoshinori
authors: Y
authors: Ohsumi
authors: Fuyuhiko
authors: F
authors: Inagaki
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000071193:Autophagy-Related Protein 7; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009097:Multienzyme Complexes; D009154:Mutation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D013997:Time Factors; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000378:metabolism
chemical_list: C114830:ATG7 protein, S cerevisiae; C113757:ATG8 protein, S cerevisiae; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D008869:Microtubule-Associated Proteins; D009097:Multienzyme Complexes; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; D044763:Ubiquitin-Conjugating Enzymes; D000071193:Autophagy-Related Protein 7; C104235:ATG3 protein, S cerevisiae