Structure of TonB in Complex with FhuA,
            <i>E. coli</i>
            Outer Membrane Receptor

Pawelek, Peter D.; Croteau, Nathalie; Ng-Thow-Hing, Christopher; Khursigara, Cezar M.; Moiseeva, Natalia; Allaire, Marc; Coulton, James W.

doi:10.1126/science.1128057

Cited by 247 publications

(297 citation statements)

References 17 publications

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“…An independent test of this model came with the recent determination of the structure of the periplasmic domain of TonB in complex with two TonB-dependent receptors, FhuA (23) and BtuB (24). The coevolving signaling network bifurcates near the periplasmic surface of the transporter, with the first branch ending in the pocket containing the switch helix and the TonB-box and the second extending across the periplasmic surface of the plug to the opposite side of the barrel (Fig.…”

Section: Discussionmentioning

confidence: 99%

Signal transduction pathway of TonB-dependent transporters

Ferguson

Amezcua²,

Halabi³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Transcription of the ferric citrate import system is regulated by ferric citrate binding to the outer membrane transporter FecA. A signal indicating transporter occupancy is relayed across the outer membrane to energy-transducing and regulatory proteins embedded in the cytoplasmic membrane. Because transcriptional activation is not coupled to ferric citrate import, an allosteric mechanism underlies this complex signaling mechanism. Using evolutionbased statistical analysis we have identified a sparse but structurally connected network of residues that links distant functional sites in FecA. Functional analyses of these positions confirm their involvement in the mechanism that regulates transcriptional activation in response to ferric citrate binding at the cell surface. This mechanism appears to be conserved and provides the structural basis for the allosteric signaling of TonB-dependent transporters.bacterial iron transport ͉ NMR ͉ signaling domain ͉ statistical coupling analysis

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Section: Discussionmentioning

confidence: 99%

Signal transduction pathway of TonB-dependent transporters

Ferguson

Amezcua²,

Halabi³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…TonB is a three-domain protein containing an N-terminal transmembrane helix that anchors the protein in the cytoplasmic membrane, a central proline-rich domain that resides within the periplasm and a C-terminal globular domain that directly contacts outer membrane receptors. Two structures of the C-terminal domain of TonB complexed with an outer membrane receptor are now available (Pawelek et al 2006;Shultis et al 2006).…”

Section: Biological Contextmentioning

confidence: 99%

1H, 13C and 15N resonance assignments of the C-terminal domain of HasB, a specific TonB like protein, from Serratia marcescens

et al. 2007

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“…Over the past three decades, many aspects of this TonB-ExbB-ExbD-dependent transport system have been revealed. The crystal structures of several OM transporters and their complexes with TonB are now known (Ferguson et al, 1998(Ferguson et al, , 2002Buchanan et al, 1999;Ferguson and Deisenhofer, 2004;Pawelek et al, 2006;Shultis et al, 2006;Krieg et al, 2009), the signal transduction of OM transporters by interaction with TonB has been elucidated (Ferguson et al, 2007;Kim et al, 2007) and the rotational mechanism of TonB motion has been reported (Jordan et al, 2013). However, with regard to the substrates of the transport system, we are probably only seeing the 'tip of the iceberg' (Schauer et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

New insights into iron acquisition by cyanobacteria: an essential role for ExbB-ExbD complex in inorganic iron uptake

Jiang

Lou

et al. 2014

The ISME Journal

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Cyanobacteria are globally important primary producers that have an exceptionally large iron requirement for photosynthesis. In many aquatic ecosystems, the levels of dissolved iron are so low and some of the chemical species so unreactive that growth of cyanobacteria is impaired. Pathways of iron uptake through cyanobacterial membranes are now being elucidated, but the molecular details are still largely unknown. Here we report that the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 contains three exbB-exbD gene clusters that are obligatorily required for growth and are involved in iron acquisition. The three exbB-exbDs are redundant, but single and double mutants have reduced rates of iron uptake compared with wild-type cells, and the triple mutant appeared to be lethal. Short-term measurements in chemically well-defined medium show that iron uptake by Synechocystis depends on inorganic iron (Fe 0 ) concentration and ExbB-ExbD complexes are essentially required for the Fe 0 transport process. Although transport of iron bound to a model siderophore, ferrioxamine B, is also reduced in the exbB-exbD mutants, the rate of uptake at similar total [Fe] is about 800-fold slower than Fe 0 , suggesting that hydroxamate siderophore iron uptake may be less ecologically relevant than free iron. These results provide the first evidence that ExbB-ExbD is involved in inorganic iron uptake and is an essential part of the iron acquisition pathway in cyanobacteria. The involvement of an ExbB-ExbD system for inorganic iron uptake may allow cyanobacteria to more tightly maintain iron homeostasis, particularly in variable environments where iron concentrations range from limiting to sufficient.

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Structure of TonB in Complex with FhuA, E. coli Outer Membrane Receptor

Cited by 247 publications

References 17 publications

Signal transduction pathway of TonB-dependent transporters

Signal transduction pathway of TonB-dependent transporters

1H, 13C and 15N resonance assignments of the C-terminal domain of HasB, a specific TonB like protein, from Serratia marcescens

New insights into iron acquisition by cyanobacteria: an essential role for ExbB-ExbD complex in inorganic iron uptake

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