1xx3
Solution Structure of Escherichia coli TonB-CTD
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OverviewOverview
The TonB protein transduces energy from the proton gradient across the, cytoplasmic membrane of Gram-negative bacteria to TonB-dependent outer, membrane receptors. It is a critically important protein in iron uptake, and deletion of this protein is known to decrease virulence of bacteria in, animal models. This system has been used for Trojan horse antibiotic, delivery. Here, we describe the high-resolution solution structure of, Escherichia coli TonB residues 103-239 (TonB-CTD). TonB-CTD is monomeric, with an unstructured N terminus (103-151) and a well structured C terminus, (152-239). The structure contains a four-stranded antiparallel beta-sheet, packed against two alpha-helices and an extended strand in a configuration, homologous to the C-terminal domain of the TolA protein. Chemical shift, perturbations to the TonB-CTD (1)H-(15)N HSCQ spectrum titrated with TonB, box peptides modeled from the E.coli FhuA, FepA and BtuB proteins were all, equivalent, indicating that all three peptides bind to the same region of, TonB. Isothermal titration calorimetry measurements demonstrate that, TonB-CTD interacts with the FhuA-derived peptide with a K(D)=36(+/-7), microM. On the basis of chemical shift data, the position of Gln160, and, comparison to the TolA gp3 N1 complex crystal structure, we propose that, the TonB box binds to TonB-CTD along the beta3-strand.
About this StructureAbout this Structure
1XX3 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
The solution structure of the C-terminal domain of TonB and interaction studies with TonB box peptides., Sean Peacock R, Weljie AM, Peter Howard S, Price FD, Vogel HJ, J Mol Biol. 2005 Feb 4;345(5):1185-97. Epub 2004 Dec 15. PMID:15644214
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