6h6f

PTC3 holotoxin complex from Photorhabdus luminiscens - Mutant TcC-D651APTC3 holotoxin complex from Photorhabdus luminiscens - Mutant TcC-D651A

6h6f, resolution 3.72Å Show:Asymmetric Unit Biological Assembly Structural highlights 6h6f is a 6 chain structure with sequence from Atcc 29999. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: tcdA, tcdA1 (ATCC 29999), TccC3 (ATCC 29999) Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Tc toxins secrete toxic enzymes into host cells using a unique syringe-like injection mechanism. They are composed of three subunits, TcA, TcB and TcC. TcA forms the translocation channel and the TcB-TcC heterodimer functions as a cocoon that shields the toxic enzyme. Binding of the cocoon to the channel triggers opening of the cocoon and translocation of the toxic enzyme into the channel. Here we show in atomic detail how the assembly of the three components activates the toxin. We find that part of the cocoon completely unfolds and refolds into an alternative conformation upon binding. The presence of the toxic enzyme inside the cocoon is essential for its subnanomolar binding affinity for the TcA subunit. The enzyme passes through a narrow negatively charged constriction site inside the cocoon, probably acting as an extruder that releases the unfolded protein with its C terminus first into the translocation channel. Tc toxin activation requires unfolding and refolding of a beta-propeller.,Gatsogiannis C, Merino F, Roderer D, Balchin D, Schubert E, Kuhlee A, Hayer-Hartl M, Raunser S Nature. 2018 Sep 19. pii: 10.1038/s41586-018-0556-6. doi:, 10.1038/s41586-018-0556-6. PMID:30232455 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.