Atomic Structure and Phospholipid Binding Properties of the <i>Francisella</i> Type VI Secretion System Effector Protein PdpC.

ABSTRACT: Francisella tularensis, a gram-negative facultative intracellular pathogen, causes tularemia, a potentially fatal infection. The Francisella pathogenicity island (FPI) encodes a type VI secretion system (T6SS), critical for the bacterium's ability to replicate within host cells and cause disease. PdpC, an FPI-encoded T6SS effector protein, is essential for phagosomal escape, intracellular replication, and virulence in animals, yet its structure and function remain poorly understood. Here, we expressed PdpC recombinantly and determined the cryoEM structure of PdpC at 3.4 Å resolution, revealing a monomeric 156 kDa protein with a seahorse-shaped architecture (80 Å × 75 Å × 120 Å). PdpC comprises five domains: an N-terminal domain (NTD) forming a prominent lateral head lobe, a c

SUBMITTER: Liu X 

PROVIDER: S-EPMC12247734 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature