Tc-complex (image) Max-Planck-Gesellschaft Caption This figure shows structural changes to the TcA toxin during the nanoinjection. The toxin is activated by pH changes. As a result, the exterior shell (green) opens and the stretched molecular spring (black) can contract. In doing so, it pulls the central channel (yellow) along with it. Credit MPI f. Molecular Physiology/ Gatsogiannis, Raunser Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.