4jiw | pdb_00004jiw

c1882 PAAR-repeat protein from Escherichia coli in complex with a VgrG-like beta-helix that is based on a fragment of T4 gp5

spinqualitylabelsall models 4jiw, resolution 3.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4jiw is a 16 chain structure with sequence from Escherichia coli CFT073 and Escherichia virus T4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, MG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NEEDL_BPT4 Tail-associated lysozyme of the baseplate hub that is essential for localized hydrolysis of bacterial cell wall necessary for viral DNA injection. The needle-like gp5 protein punctures the outer cell membrane and then digests the peptidoglycan cell wall in the periplasmic space. Involved in the tail assembly. Publication Abstract from PubMed The bacterial type VI secretion system (T6SS) is a large multicomponent, dynamic macromolecular machine that has an important role in the ecology of many Gram-negative bacteria. T6SS is responsible for translocation of a wide range of toxic effector molecules, allowing predatory cells to kill both prokaryotic as well as eukaryotic prey cells. The T6SS organelle is functionally analogous to contractile tails of bacteriophages and is thought to attack cells by initially penetrating them with a trimeric protein complex called the VgrG spike. Neither the exact protein composition of the T6SS organelle nor the mechanisms of effector selection and delivery are known. Here we report that proteins from the PAAR (proline-alanine-alanine-arginine) repeat superfamily form a sharp conical extension on the VgrG spike, which is further involved in attaching effector domains to the spike. The crystal structures of two PAAR-repeat proteins bound to VgrG-like partners show that these proteins sharpen the tip of the T6SS spike complex. We demonstrate that PAAR proteins are essential for T6SS-mediated secretion and target cell killing by Vibrio cholerae and Acinetobacter baylyi. Our results indicate a new model of the T6SS organelle in which the VgrG-PAAR spike complex is decorated with multiple effectors that are delivered simultaneously into target cells in a single contraction-driven translocation event. PAAR-repeat proteins sharpen and diversify the type VI secretion system spike.,Shneider MM, Buth SA, Ho BT, Basler M, Mekalanos JJ, Leiman PG Nature. 2013 Aug 15;500(7462):350-3. doi: 10.1038/nature12453. Epub 2013 Aug 7. PMID:23925114 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lysozyme 3D structures

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