ArticleJournal of molecular biology2009
Coupling of calcium and substrate binding through loop alignment in the outer-membrane transporter BtuB.
Article in Journal of molecular biology, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers.
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Who cites it
13 citing papers in PubMed, 33 citations in OpenAlex.
- Native Cell Environment Constrains Loop Structure in the Escherichia coli Cobalamin Transporter BtuB.Biophysical journal · 2020Article
- Extracellular loops of BtuB facilitate transport of vitamin B12 through the outer membrane of E. coli.PLoS computational biology · 2020Article
- Presence of substrate aids lateral gate separation in LptD.Biochimica et biophysica acta. Biomembranes · 2020Article
- Development of CHARMM-Compatible Force-Field Parameters for Cobalamin and Related Cofactors from Quantum Mechanical Calculations.Journal of chemical theory and computation · 2018Article
- Gating of TonB-dependent transporters by substrate-specific forced remodelling.Nature communications · 2017Article
- Allosteric Signaling Is Bidirectional in an Outer-Membrane Transport Protein.Biophysical journal · 2016Article
- Role of the Native Outer-Membrane Environment on the Transporter BtuB.Biophysical journal · 2016Article
- Interaction of a partially disordered antisigma factor with its partner, the signaling domain of the TonB-dependent transporter HasR.PloS one · 2014Article
- Article
- Visualizing functional motions of membrane transporters with molecular dynamics simulations.Biochemistry · 2013Review
- Article
- Molecular basis for the activation of a catalytic asparagine residue in a self-cleaving bacterial autotransporter.Journal of molecular biology · 2012Article
- Capturing Functional Motions of Membrane Channels and Transporters with Molecular Dynamics Simulation.Journal of computational and theoretical nanoscience · 2010Article
Corrections and comments
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Authors and funding
3 authors at 2 institutions in 1 country.
Funding
Abstract
In Gram-negative bacteria, TonB-dependent outer-membrane transporters bind large, scarce organometallic substrates with high affinity preceding active transport. The cobalamin transporter BtuB requires the additional binding of two Ca(2+) ions before substrate binding can occur, but the underlying molecular mechanism is unknown. Using the crystallographic structures available for different bound states of BtuB, we have carried out extended molecular dynamics simulations of multiple functional states of BtuB to address the role of Ca(2+) in substrate recruitment. We find that Ca(2+) binding both stabilizes and repositions key extracellular loops of BtuB, optimizing interactions with the substrate. Interestingly, replacement by Mg(2+) abolishes this effect, in accordance with experiments. Using a set of new force-field parameters developed for cyanocobalamin, we also simulated the substrate-bound form of BtuB, where we observed interactions not seen in the crystal structure between the substrate and loops previously found to be important for binding and transport. Based on our results, we suggest that the large size of cobalamin compared to other TonB-dependent transporter substrates explains the requirement of Ca(2+) binding for high-affinity substrate recruitment in BtuB.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.