Molecular mechanism of complement interference by Streptococcus pyogenes nuclease A.

Streptococcus pyogenes nuclease A inhibits complement activation by preventing membrane attack complex assembly, revealing a novel immune evasion mechanism.

• Why it matters: Understanding how bacteria evade host immunity is crucial for developing effective treatments, as the molecular details of these interactions are often poorly understood.
• What they did: The study used hydrogen-deuterium exchange mass spectrometry, cryo-EM, and mass spectrometry to analyze SpnA's structure and interactions, identifying conserved binding interfaces with complement component C5b67.
• The result: Findings demonstrate that SpnA blocks MAC formation, offering new targets for therapeutic intervention against S. pyogenes infections and advancing knowledge of bacterial immune evasion strategies.