ArticleProceedings of the National Academy of Sciences of the United States of America2003
Competing ligands stabilize alternate conformations of the energy coupling motif of a TonB-dependent outer membrane transporter.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2003. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 22 papers.
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Who cites it
22 citing papers in PubMed, 36 citations in OpenAlex.
- Substrate Uptake by TonB-Dependent Outer Membrane Transporters.Molecular microbiology · 2024Review
- Location, Location, Location: Establishing Design Principles for New Antibacterials from Ferric Siderophore Transport Systems.Molecules (Basel, Switzerland) · 2024Review
- HDX-MS performed on BtuB inProceedings of the National Academy of Sciences of the United States of America · 2022Article
- Vitamin BBiophysical journal · 2021Article
- Insights into SusCD-mediated glycan import by a prominent gut symbiont.Nature communications · 2021Article
- Extracellular loops of BtuB facilitate transport of vitamin B12 through the outer membrane of E. coli.PLoS computational biology · 2020Article
- Structure and Stoichiometry of the Ton Molecular Motor.International journal of molecular sciences · 2020Review
- The complex of ferric-enterobactin with its transporter from Pseudomonas aeruginosa suggests a two-site model.Nature communications · 2019Article
- Characterization of and lipopolysaccharide binding to the E. coli LptC protein dimer.Protein science : a publication of the Protein Society · 2018Article
- Going Outside the TonB Box: Identification of Novel FepA-TonB InteractionsJournal of bacteriology · 2017Article
- Gating of TonB-dependent transporters by substrate-specific forced remodelling.Nature communications · 2017Article
- Monomeric TonB and the Ton box are required for the formation of a high-affinity transporter-TonB complex.Biochemistry · 2013Article
- Use of a molecular decoy to segregate transport from antigenicity in the FrpB iron transporter from Neisseria meningitidis.PloS one · 2013Article
- Conformational exchange in a membrane transport protein is altered in protein crystals.Biophysical journal · 2010Article
- TonB-dependent transporters: regulation, structure, and function.Annual review of microbiology · 2010Review
- Ras nanoclusters: molecular structure and assembly.Seminars in cell & developmental biology · 2007Review
- Molecular basis for substrate-dependent transmembrane signaling in an outer-membrane transporter.Journal of molecular biology · 2007Article
- Deletion and substitution analysis of the Escherichia coli TonB Q160 region.Journal of bacteriology · 2007Article
- In meso structure of the cobalamin transporter, BtuB, at 1.95 A resolution.Journal of molecular biology · 2006Article
- Substrate-dependent unfolding of the energy coupling motif of a membrane transport protein determined by double electron-electron resonance.Biochemistry · 2006Article
Corrections and comments
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Authors and funding
4 authors at 1 institution in 1 country.
Funding
Abstract
BtuB is a TonB-dependent outer-membrane transporter for vitamin B12 (or cyanocobalamin, CN-Cbl) in Escherichia coli. The binding of CN-Cbl is believed to promote an unfolding or undocking of the Ton box, the conserved N-terminal energy coupling motif at the periplasmic surface of the transporter. This structural change may facilitate the interaction of BtuB with the inner membrane protein TonB. In this work, the effect of the receptor binding fragment of colicin E3 (E3R) on the conformation of the Ton box was examined with site-directed spin labeling. Addition of E3R reverses the undocking of the Ton box that is promoted by CN-Cbl, consistent with a competitive binding between the substrate and the colicin fragment. EPR spectroscopy indicates that the Ton box is in a two-state equilibrium between docked and undocked conformations. In the absence of substrate, the docked conformation is the predominant state; however, the equilibrium can be shifted to the undocked state by the addition of detergents or site-specific proline substitutions. Even when the undocking is induced by detergents or by certain proline mutations, E3R binding shifts the equilibrium to the docked conformation. Thus, two competitive extracellular ligands, CN-Cbl and ER3, transduce opposite conformations of the N-terminal Ton box. Substrate binding stabilizes an undocked conformation, whereas E3R binding stabilizes a docked conformation of the Ton box.
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