3o0e

Crystal structure of OmpF in complex with colicin peptide OBS1

spinqualitylabelsall models 3o0e, resolution 3.01Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3o0e is a 12 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BOG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [CEA9_ECOLX] This plasmid-coded bactericidal protein is an endonuclease active on both single- and double-stranded DNA but with undefined specificity. Colicins are polypeptide toxins produced by and active against E.coli and closely related bacteria. Publication Abstract from PubMed The porins OmpF and OmpC are trimeric beta-barrel proteins with narrow channels running through each monomer that exclude molecules > 600 Da while mediating the passive diffusion of small nutrients and metabolites across the Gram-negative outer membrane (OM). Here, we elucidate the mechanism by which an entire soluble protein domain (> 6 kDa) is delivered through the lumen of such porins. Following high-affinity binding to the vitamin B(12) receptor in Escherichia coli, the bacteriocin ColE9 recruits OmpF or OmpC using an 83-residue intrinsically unstructured translocation domain (IUTD) to deliver a 16-residue TolB-binding epitope (TBE) in the center of the IUTD to the periplasm where it triggers toxin entry. We demonstrate that the IUTD houses two OmpF-binding sites, OBS1 (residues 2-18) and OBS2 (residues 54-63), which flank the TBE and bind with K(d)s of 2 and 24 muM, respectively, at pH 6.5 and 25 masculineC. We show the two OBSs share the same binding site on OmpF and that the colicin must house at least one of them for antibiotic activity. Finally, we report the structure of the OmpF-OBS1 complex that shows the colicin bound within the porin lumen spanning the membrane bilayer. Our study explains how colicins exploit porins to deliver epitope signals to the bacterial periplasm and, more broadly, how the inherent flexibility and narrow cross-sectional area of an IUP domain can endow it with the ability to traverse a biological membrane via the constricted lumen of a beta-barrel membrane protein. Directed epitope delivery across the Escherichia coli outer membrane through the porin OmpF.,Housden NG, Wojdyla JA, Korczynska J, Grishkovskaya I, Kirkpatrick N, Brzozowski AM, Kleanthous C Proc Natl Acad Sci U S A. 2010 Nov 22. PMID:21098297 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Colicin 3D structures Porin 3D structures

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