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Crystal Structure of Autophagy-Associated Protein 8 at 1.36 Å Resolution and Its Inhibitory Interactions with Indole Analogs

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Autophagy-associated protein 8 (ATG8) is essential for autophagy and organismal growth and development. In this study, we successfully resolved the crystal structure of Drosophila melanogaster ( D. melanogaster ) ATG8a ( Dm ATG8a) at 1.36 Å resolution. Being distinct from previously characterized ATG8 homologues, Dm ATG8a (121 residues) adopts a unique fold comprising five α-helices and four β-folding strands, in contrast to the canonical four α-helices and four β-folding strands observed in other ATG8 proteins. Dm ATG8a features two active cavities: hydrophobic pocket 1 (HP1) and hydrophobic pocket 2 (HP2), which are essential for the normal physiological function of ATG8. Indole and its analogs can bind specifically with HP1. Microscale thermophoresis results demonstrated a strong affinity of 6-fluoroindole with Dm ATG8a (3.54 μmol/L), but no affinity with the Dm ATG8a K48A mutant, suggesting that Lys48 is critical in binding 6-fluoroindole probably via a hydrogen bond interaction. The half-maximum lethal concentration (LC 50 ) of 6-fluoroindole against D. melanogaster adult flies was 169 μg/mL. Our findings establish Dm ATG8a as a promising target for developing indole-based insecticides.

Source: Journal of Agricultural and Food Chemistry

DOI: 10.1021/acs.jafc.4c11205