The yxiD gene from Bacillus subtilis 6633 encodes a polymorphic toxin with tRNase activity and is neutralized by the cognate immunity protein YxxD.

ABSTRACT: Polymorphic toxin systems (PTS) are widespread and play an important role in bacterial competition and shaping communities. However, these systems are less studied in Gram-positive bacteria. Here, we structurally and functionally characterized YxiD-YxxD, a predicted member of PTS from Bacillus subtilis 6633. Using growth curve assays, we established that YxiD-YxxD codes for a toxin-immunity protein pair. We determined a 1.7 Å resolution crystal structure of the YxiDCTDH528A (C-terminal domain of YxiD) toxin bound to its cognate immunity protein YxxD. Structure revealed that the toxin adopts a Barnase/EndoU/colicin/RelE (BECR) fold, a characteristic of RNase toxins and the immunity protein sterically occludes binding of the molecular substrate to neutralize the toxin. Structural and other b

SUBMITTER: Rohilla R 

PROVIDER: S-EPMC12700104 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature