Exploring the antimicrobial potential of streptococcal fratricins

Zoocin A from Streptococcus agalactiae shows the broadest fratricin target range, including activity against Streptococcus mutans and Streptococcus sobrinus linked to dental caries.

• Why it matters: Fratricide during natural transformation kills closely related streptococci to free DNA, but fratricins’ antimicrobial scope and practical stability under physiological conditions remain to be mapped.
• What they did: The study screened nine putative fratricins, purified Zoocin A, ScrM, and CbpD-ves, and characterized activity and stability under physiologically relevant pH, temperature, and ionic strength.
• The result: Zoocin A, ScrM, and CbpD-ves predominantly targeted streptococci, with Zoocin A requiring cations (Ca2+ and Mn2+) and both localizing peptidoglycan cleavage to the septal region of dividing cells.