Structure of Atg5.Atg16, a complex essential for autophagy

Atg5 is covalently modified with a ubiquitin-like modifier, Atg12, and the Atg12-Atg5 conjugate further forms a complex with the multimeric protein Atg16. The Atg12-Atg5·Atg16 multimeric complex plays an essential role in autophagy, the bulk degradation system conserved in all eukaryotes. We report here the crystal structure of Atg5 complexed with the N-terminal region of Atg16 at 1.97 Å resolution. Atg5 is comprised of two ubiquitin-like domains that flank a helix-rich domain. The N-terminal region of Atg16 has a helical structure and is bound to the groove formed by these three domains. In vitr