5 results match your criteria contacts btub

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Evidence for the Supramolecular Organization of a Bacterial Outer-Membrane Protein from In Vivo Pulse Electron Paramagnetic Resonance Spectroscopy.

J Am Chem Soc 2020 06 8;142(24):10715-10722. Epub 2020 Jun 8.

In the outer membrane of Gram-negative bacteria, membrane proteins are thought to be organized into domains or islands that play a role in the segregation, movement, and turnover of membrane components. However, there is presently limited information on the structure of these domains or the molecular interactions that mediate domain formation. In the present work, the outer membrane vitamin B transporter, BtuB, was spin-labeled, and double electron-electron resonance was used to measure the distances between proteins in intact cells. Read More

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A Dynamic Protein-Protein Coupling between the TonB-Dependent Transporter FhuA and TonB.

Biochemistry 2018 02 26;57(6):1045-1053. Epub 2018 Jan 26.

Department of Chemistry and Center for Membrane Biology, University of Virginia , McCormick Road, Charlottesville, Virginia 22904, United States.

Bacterial outer membrane TonB-dependent transporters function by executing cycles of binding and unbinding to the inner membrane protein TonB. In the vitamin B transporter BtuB and the ferric citrate transporter FecA, substrate binding increases the periplasmic exposure of the Ton box, an energy-coupling segment. This increased exposure appears to enhance the affinity of the transporter for TonB. Read More

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February 2018

Phage display reveals multiple contact sites between FhuA, an outer membrane receptor of Escherichia coli, and TonB.

J Mol Biol 2006 Mar 27;357(1):236-51. Epub 2005 Dec 27.

Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, Que., Canada H3A 2B4.

The ferric hydroxamate uptake receptor FhuA from Escherichia coli transports siderophores across the outer membrane (OM). TonB-ExbB-ExbD transduces energy from the cytoplasmic membrane to the OM by contacts between TonB and OM receptors that contain the Ton box, a consensus sequence near the N terminus. Although the Ton box is a region of known contact between OM receptors and TonB, our biophysical studies established that TonB binds to FhuA through multiple regions of interaction. Read More

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Problems in obtaining diffraction-quality crystals of hetero-oligomeric integral membrane proteins.

J Struct Funct Genomics 2005 ;6(2-3):219-23

Department of Biological Sciences, Lilly Hall of Life Sciences, Purdue University, West Lafayette, IN 47907-2054, USA.

The major barrier responsible for the slow pace of structure determination of integral membrane proteins is the difficulty of crystallizing detergent-solubilized hydrophobic proteins, particularly hetero-oligomeric integral membrane proteins. For the latter class of multi-subunit proteins, we have encountered the following problems in addition to the ubiquitous problem of detergent compatibility: (i) instability caused by over-purification that results in delipidation; (ii) protease activity degrading exposed loops and termini of subunits of the complex that could not be inhibited; (iii) poor protein-protein contacts presumably arising from masking by the detergent micelle. Problem (i) could be ameliorated in crystallization of the cytochrome b(6)f complex by augmenting the delipidated complex with synthetic lipid. Read More

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Substrate-induced exposure of an energy-coupling motif of a membrane transporter.

Nat Struct Biol 2000 Mar;7(3):205-9

Department of Chemistry and Biophysics Program, University of Virginia, Charlottesville 22901, USA.

BtuB is an outer membrane protein responsible for the uptake of vitamin B12 by Escherichia coli. It belongs to a family of bacterial transport proteins that derive energy for transport by coupling to the trans-periplasmic energy-coupling protein TonB. Using site-directed spin labeling and EPR we investigated the structure and substrate-induced changes in the TonB box, a highly conserved region in all TonB dependent transporters that may couple to TonB. Read More

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