Insights into noncanonical E1 enzyme activation from the structure of autophagic E1 Atg7 with Atg8

The mechanism by which the noncanonical E1-like enzyme Atg7 activates ubiquitin-like Atg8 to trigger autophagy has not been well understood. The crystal structures of the N-terminal domain of Atg7 alone and C-terminal domain of Atg7 in complex with Atg8 show that this probably proceeds without the need for dramatic conformational rearrangements by Atg7, distinct from other E1 enzymes.