Cryo-EM reveals the quaternary architecture of TenpIN type III toxin-antitoxin RNP complex common to pathogenic bacteria.

Cryo-EM reveals that the TenpIN type III toxin-antitoxin complex forms a unique hetero-tetramer with two proteins and two RNAs, advancing understanding of bacterial defense systems.

• Why it matters: Understanding the structure of TenpIN systems is crucial because they are widespread in pathogenic bacteria and play a key role in anti-phage defense, yet their architecture was previously unknown.
• What they did: The study used cryo-electron microscopy and de novo modeling to determine the structure of a TenpIN complex from pathogenic bacteria, showing it as a closed hetero-tetramer with specific RNA and protein interactions.
• The result: This structural insight reveals similarities to other TA systems and highlights the diversity of their architectures, enabling better understanding of bacterial immune mechanisms and potential therapeutic targets.