Crystal Structure of a 92-Residue C-terminal Fragment of TonB from Escherichia coli Reveals Significant Conformational Changes Compared to Structures of Smaller TonB Fragments

Ködding, Jiri; Killig, Frank; Polzer, Patrick; Howard, S. Peter; Diederichs, Kay; Welte, Wolfram

doi:10.1074/jbc.m411155200

Cited by 59 publications

(54 citation statements)

References 48 publications

(65 reference statements)

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“…Interaction studies of FhuA with TonB showed an intermediate 1:1 complex and a stable 1:2 complex, the latter of which increased upon the addition of ferricrocin as an FhuA ligand (164). These findings are supported by the crystal structure of the C-terminal domain of TonB, revealing dimer formation, which, however, seems to depend on the length of the recombinant protein fragments chosen (169). A crystal structure of FhuA in complex with the TonB C-terminal domain was solved recently (245), which showed the interaction between the receptor and the energy transducer in more detail (Fig.…”

Section: General Steps Of Siderophore Pathwayssupporting

confidence: 71%

Siderophore-Based Iron Acquisition and Pathogen Control

Miethke

Marahiel

2007

Microbiol Mol Biol Rev

1,413

1,302

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SUMMARY High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as “Trojan horse” toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.

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Section: General Steps Of Siderophore Pathwayssupporting

confidence: 71%

Siderophore-Based Iron Acquisition and Pathogen Control

Miethke

Marahiel

2007

Microbiol Mol Biol Rev

1,413

1,302

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“…15,16 It was also in accord with the observation of conformational transitions in the structure of some receptors on the periplasmic side after binding of cargo molecules. 17,18 Crystal and NMR structures of the C-terminal globular domain of TonB alone 15,19 and in complex with outer membrane receptors 20,21 have been reported. In the complexes the domain was in contact with the socalled TonB-box of the receptors, a conserved stretch of $7 amino acids near the periplasmic N-terminal end of the cork domain.…”

Section: Introductionsupporting

confidence: 62%

The proline‐rich domain of TonB possesses an extended polyproline II‐like conformation of sufficient length to span the periplasm of Gram‐negative bacteria

et al. 2010

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TonB from Escherichia coli and its homologues are critical for the uptake of siderophores through the outer membrane of Gram-negative bacteria using chemiosmotic energy. When different models for the mechanism of TonB mediated energy transfer from the inner to the outer membrane are discussed, one of the key questions is whether TonB spans the periplasm. In this article, we use long range distance measurements by spin-label pulsed EPR (Double Electron-Electron Resonance, DEER) and CD spectroscopy to show that the proline-rich segment of TonB exists in a PPII-like conformation. The result implies that the proline-rich segment of TonB possesses a length of more than 15 nm, sufficient to span the periplasm of Gram-negative bacteria.

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“…3) to cluster at three discrete TonB regions as follows: an N-terminal domain (region I), an intermediate domain (region II), and the C-terminal domain (region III). Three-dimensional structural information has been reported (4,5,30) only for the C-terminal domain of TonB. We mapped (Fig.…”

Section: Methodsmentioning

confidence: 99%