Mechanistic insights into single-stranded DNA degradation by lysosomal exonucleases PLD3 and PLD4 from structural snapshots.

ABSTRACT: Lysosomal exonuclease phospholipase D (PLD) family PLD3 and PLD4 degrade single-stranded RNA or DNA and regulate TLR7 or TLR9 responses. Polymorphisms of these enzymes are associated with human diseases: PLD4 is associated with inflammatory diseases, and PLD3 is associated with neurodegenerative diseases. Here, we determine the structures of substrate-bound PLD3 and PLD4 by cryo-electron microscopy. Our structures reveal that PLD3 rebuilds a substrate-binding pocket, depending on the substrate, mainly via motion of the Phe335-containing loop. Furthermore, we captured the structure in a metastable state that appears during substrate rearrangement following product release. Together, our findings identify the residues that underlie the distinct activities of PLD3 and PLD4. This study provide

SUBMITTER: Hirano Y 

PROVIDER: S-EPMC12749308 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature