Periplasmic gatekeeping of phage DNA entry by an rSAM enzyme matured effector with HxS repeats - PubMed
4 hours ago
- #antiphage defense
- #phage DNA entry
- #rSAM enzymes
- The HXS system is a bacterial antiphage defense mechanism that inhibits phage DNA entry.
- It consists of two radical S-adenosylmethionine (rSAM) enzymes (HxsB and HxsC), a small protein (HxsD), and the effector HxsA with a peptidoglycan-binding domain and five His-Xaa-Ser (HXS) repeats.
- HxsB and HxsC catalyze the maturation of HxsA, including N-terminal processing and a site-specific +8 Da modification, producing a periplasmic effector required for defense.
- The matured effector likely engages incoming phage DNA electrostatically to arrest its entry, providing broad-spectrum and robust antiphage activity.
- This study presents the first demonstration of a system specifically inhibiting phage genomic DNA ejection.