1XX3

Solution Structure of Escherichia coli TonB-CTD

Summary for 1XX3

• Entry DOI: 10.2210/pdb1xx3/pdb
• Descriptor: TonB protein (1 entity in total)
• Functional Keywords: tonb-ctd, c-terminal domain, transport protein
• Biological source: Escherichia coli
• Cellular location: Cell inner membrane; Single-pass membrane protein; Periplasmic side: P02929
• Total number of polymer chains: 1
• Total formula weight: 16036.27

Authors

Peacock, R.S.,Weljie, A.M.,Howard, S.P.,Price, F.D.,Vogel, H.J. (deposition date: 2004-11-03, release date: 2005-02-15, Last modification date: 2024-05-22)

Primary citation

Peacock, R.S.,Weljie, A.M.,Howard, S.P.,Price, F.D.,Vogel, H.J.
The solution structure of the C-terminal domain of TonB and interaction studies with TonB box peptides
J.Mol.Biol., 345:1185-1197, 2005

PubMed Abstract: 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.

PubMed: 15644214
DOI: 10.1016/j.jmb.2004.11.026

Experimental method

SOLUTION NMR