16183633 , Related PDB id: 2CY7
- Sugawara K, Suzuki NN, Fujioka Y, Mizushima N, Ohsumi Y, Inagaki F
- Structural basis for the specificity and catalysis of human Atg4B responsible for mammalian autophagy.
- J Biol Chem. 2005 Dec 2;280(48):40058-65. Epub 2005 Sep 23.
- Reversible modification of Atg8 with phosphatidylethanolamine is crucial for autophagy, the bulk degradation system conserved in eukaryotic cells. Atg4 is a novel cysteine protease that processes and deconjugates Atg8. Herein, we report the crystal structure of human Atg4B (HsAtg4B) at 1.9-A resolution. Despite no obvious sequence homology with known proteases, the structure of HsAtg4B shows a classical papain-like fold. In addition to the papain fold region, HsAtg4B has a small alpha/beta-fold domain. This domain is thought to be the binding site for Atg8 homologs. The active site cleft of HsAtg4B is masked by a loop (residues 259-262), implying a conformational change upon substrate binding. The structure and in vitro mutational analyses provide the basis for the specificity and catalysis of HsAtg4B. This will enable the design of Atg4-specific inhibitors that block autophagy.