8uee

Atomic structure of Salmonella SipA/F-actin complex by cryo-EM

spinqualitylabelsall models 8uee, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8uee is a 11 chain structure with sequence from Oryctolagus cuniculus and Salmonella enterica subsp. enterica serovar Typhimurium str. LT2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.2Å Ligands: ADP, HIC, MG, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ACTS_RABIT Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. Publication Abstract from PubMed Entry of Salmonella into host enterocytes relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a 1:2 stoichiometry with sub-nanomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the groove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved by a combination of fast association via the core and very slow dissociation dictated by the arm. Similar to P(i), BeF(3), and phalloidin, SipA potently inhibited actin depolymerization by actin depolymerizing factor (ADF)/cofilin, which correlated with increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin.,Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS Structure. 2024 Jun 6;32(6):725-738.e8. doi: 10.1016/j.str.2024.02.022. Epub 2024 , Mar 21. PMID:38518780 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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