9nh2 | pdb_00009nh2

In situ cryo-EM structure of porin III of the Legionella Dot/Icm T4SS machine

spinqualitylabelsall models 9nh2, resolution 4.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9nh2 is a 16 chain structure with sequence from Legionella pneumophila subsp. pneumophila. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 4.05Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q5ZXK0_LEGPH Publication Abstract from PubMed The Dot/Icm machine in Legionella pneumophila is one of the most versatile type IV secretion systems (T4SSs), with a remarkable capacity to translocate over 330 different effector proteins across the bacterial envelope into host cells. At least 27 Dot and Icm proteins are required for assembly and function of the system, yet the architecture and activation mechanism remain poorly understood at the molecular level. Here, we deploy cryo-electron microscopy to reveal in-situ structures of the Dot/Icm machine at near-atomic resolution. Importantly, two proteins essential for effector translocation, DotA and IcmX, form a pentameric protochannel at an inactive state. Upon activation, the DotA-IcmX protochannel undergoes extensive rearrangements to form an extended transenvelope passage capable of transporting effector proteins from the bacterial cytoplasm into host cells as revealed by cryo-electron tomography. Collectively, our findings suggest that the DotA-IcmX complex functions as the gatekeeper for effector translocation of the Dot/Icm T4SS. In-situ structures of the Legionella Dot/Icm T4SS identify the DotA-IcmX complex as the gatekeeper for effector translocation.,Yue J, Heydari S, Park D, Chetrit D, Tachiyama S, Guo W, Botting JM, Wu S, Roy CR, Liu J bioRxiv [Preprint]. 2025 Jun 25:2025.06.23.660953. doi: , 10.1101/2025.06.23.660953. PMID:40666918 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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