Christos Gatsogiannis / Felipe Merino / Daniel Prumbaum / Daniel Roderer / Franziska Leidreiter / Dominic Meusch / Stefan Raunser /
PubMed 要旨
Tc toxins from pathogenic bacteria use a special syringe-like mechanism to perforate the host cell membrane and inject a deadly enzyme into the host cytosol. The molecular mechanism of this unusual ...Tc toxins from pathogenic bacteria use a special syringe-like mechanism to perforate the host cell membrane and inject a deadly enzyme into the host cytosol. The molecular mechanism of this unusual injection system is poorly understood. Using electron cryomicroscopy, we determined the structure of TcdA1 from Photorhabdus luminescens embedded in lipid nanodiscs. In our structure, compared with the previous structure of TcdA1 in the prepore state, the transmembrane helices rearrange in the membrane and open the initially closed pore. However, the helices do not span the complete membrane; instead, the loops connecting the helices form the rim of the funnel. Lipid head groups reach into the space between the loops and consequently stabilize the pore conformation. The linker domain is folded and packed into a pocket formed by the other domains of the toxin, thereby considerably contributing to stabilization of the pore state.
EMDB-4068, PDB-5lki: Cryo-EM structure of the Tc toxin TcdA1 in its pore state PDB-5lkh: Cryo-EM structure of the Tc toxin TcdA1 in its pore state (obtained by flexible fitting) 手法: EM (単粒子) / 解像度: 3.46 Å