ArticleJournal of bacteriology2011
Taking the Escherichia coli TonB transmembrane domain "offline"? Nonprotonatable Asn substitutes fully for TonB His20.
Article in Journal of bacteriology, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers.
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Who cites it
14 citing papers in PubMed, 26 citations in OpenAlex.
- Force-Generation by the Trans-Envelope Tol-Pal System.Frontiers in microbiology · 2022Review
- Structures of the stator complex that drives rotation of the bacterial flagellum.Nature microbiology · 2020Article
- The Intrinsically Disordered Region of ExbD Is Required for Signal Transduction.Journal of bacteriology · 2020Article
- Two novel proteins, TtpB2 and TtpD2, are essential for iron transport in the TonB2 system of Vibrio vulnificus.MicrobiologyOpen · 2020Article
- From Homodimer to Heterodimer and Back: Elucidating the TonB Energy Transduction Cycle.Journal of bacteriology · 2015Article
- ExbB cytoplasmic loop deletions cause immediate, proton motive force-independent growth arrest.Journal of bacteriology · 2013Article
- Mutations in Escherichia coli ExbB transmembrane domains identify scaffolding and signal transduction functions and exclude participation in a proton pathway.Journal of bacteriology · 2013Article
- Identification of functionally important TonB-ExbD periplasmic domain interactions in vivo.Journal of bacteriology · 2012Article
- The ttpC gene is contained in two of three TonB systems in the human pathogen Vibrio vulnificus, but only one is active in iron transport and virulence.Journal of bacteriology · 2012Article
- The ExbD periplasmic domain contains distinct functional regions for two stages in TonB energization.Journal of bacteriology · 2012Article
- ExbD mutants define initial stages in TonB energization.Journal of molecular biology · 2012Article
- The same periplasmic ExbD residues mediate in vivo interactions between ExbD homodimers and ExbD-TonB heterodimers.Journal of bacteriology · 2011Article
- Mutations in the ExbB cytoplasmic carboxy terminus prevent energy-dependent interaction between the TonB and ExbD periplasmic domains.Journal of bacteriology · 2011Article
- Death of the TonB Shuttle Hypothesis.Frontiers in microbiology · 2011Article
Corrections and comments
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Authors and funding
2 authors at 1 institution in 1 country.
Funding
Abstract
The TonB system of Gram-negative bacteria uses the proton motive force (PMF) of the cytoplasmic membrane to energize active transport of nutrients across the outer membrane. The single transmembrane domain (TMD) anchor of TonB, the energy transducer, is essential. Within that TMD, His20 is the only TMD residue that is unable to withstand alanine replacement without a loss of activity. H20 is required for a PMF-dependent conformational change, suggesting that the importance of H20 lies in its ability to be reversibly protonated and deprotonated. Here all possible residues were substituted at position 20 (H20X substitutions). The His residue was also relocated throughout the TonB TMD. Surprisingly, Asn, a structurally similar but nonprotonatable residue, supported full activity at position 20; H20S was very weakly active. All the remaining substitutions, including H20K, H20R, H20E, and H20D, the obvious candidates to mimic a protonated state or support proton translocation, were inactive. A second-site suppressor, ExbB(A39E), indiscriminately reactivated the majority of H20 substitutions and relocations, including H20V, which cannot be made protonatable. These results suggested that the TonB TMD was not on a proton conductance pathway and thus only indirectly responds to PMF, probably via ExbD.
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