A lipoprotein partner for the Escherichia coli outer membrane protein TolC

Abstract

The outer membrane protein TolC from Escherichia coli belongs to an extensive superfamily whose members are found throughout the didermal, Gram-negative bacterial lineages. The protein serves as an activated exit duct in multi-drug efflux pumps and protein secretion machinery. Many TolC homologues bear a lipid modification on the N-terminus that embeds into the inner leaflet of the outer membrane and appears to have been a conserved feature; however, the moiety is absent entirely in the E. coli TolC. We have discovered that the E. coli lipoprotein YbjP interacts extensively with the periplasmic surface of TolC and its N-terminal lipid moiety is embedded in the membrane, mimicking the intramolecular and modification-membrane interactions seen in TolC homologues. Here, we present cryo-EM structures of the MacA-MacB-TolC and AcrA-AcrB-TolC tripartite pumps complexed to YbjP. Although the association occurs spontaneously both in vitro and in vivo, the YbjP-TolC interaction is not required for efflux activity under standard laboratory conditions. YbjP may contribute to stabilising the orientation and distribution of TolC in the outer membrane, as well as the expression of transporters for tryptophan and cyclic peptide toxins.

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BibTeX RIS

BibTeX

@article{horne2026lipoprotein,
  title = {{A lipoprotein partner for the Escherichia coli outer membrane protein TolC}},
  author = {Jim Horne and Elise Kaplan and Ben Jin and Kieran Abbott and Victor Flores and Emmanouela Petsolari and Jan Gradon and Yvette Ntsogo and Andrzej Harris and Dingquan Yu and Ashraf Zarkan and Ben F Luisi},
  journal = {eLife},
  year = {2026},
  month = oct,
  doi = {10.7554/elife.110666},
  url = {https://hal.science/hal-05829478v1},
  note = {CC BY 4.0},
}

RIS

TY  - JOUR
TI  - A lipoprotein partner for the Escherichia coli outer membrane protein TolC
AU  - Jim Horne
AU  - Elise Kaplan
AU  - Ben Jin
AU  - Kieran Abbott
AU  - Victor Flores
AU  - Emmanouela Petsolari
AU  - Jan Gradon
AU  - Yvette Ntsogo
AU  - Andrzej Harris
AU  - Dingquan Yu
AU  - Ashraf Zarkan
AU  - Ben F Luisi
PY  - 2026
DA  - 2026/10/21
JO  - eLife
DO  - 10.7554/elife.110666
UR  - https://hal.science/hal-05829478v1
AB  - The outer membrane protein TolC from Escherichia coli belongs to an extensive superfamily whose members are found throughout the didermal, Gram-negative bacterial lineages. The protein serves as an activated exit duct in multi-drug efflux pumps and protein secretion machinery. Many TolC homologues bear a lipid modification on the N-terminus that embeds into the inner leaflet of the outer membrane and appears to have been a conserved feature; however, the moiety is absent entirely in the E. coli TolC. We have discovered that the E. coli lipoprotein YbjP interacts extensively with the periplasmic surface of TolC and its N-terminal lipid moiety is embedded in the membrane, mimicking the intramolecular and modification-membrane interactions seen in TolC homologues. Here, we present cryo-EM structures of the MacA-MacB-TolC and AcrA-AcrB-TolC tripartite pumps complexed to YbjP. Although the association occurs spontaneously both in vitro and in vivo, the YbjP-TolC interaction is not required for efflux activity under standard laboratory conditions. YbjP may contribute to stabilising the orientation and distribution of TolC in the outer membrane, as well as the expression of transporters for tryptophan and cyclic peptide toxins.
SN  - 2050-084X
ER  -

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