Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt

Research output: Contribution to journalArticleResearchpeer review

Authors

  • A. Gilardi
  • S. P. Bhamidimarri
  • M. Brönstrup
  • U. Bilitewski
  • R. K.R. Marreddy
  • K. M. Pos
  • L. Benier
  • P. Gribbon
  • M. Winterhalter
  • B. Windshügel

External Research Organisations

  • Fraunhofer Institute for Molecular Biology and Applied Ecology IME
  • Jacobs University Bremen
  • Helmholtz Centre for Infection Research (HZI)
  • Goethe University Frankfurt
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Details

Original languageEnglish
Pages (from-to)2702-2709
Number of pages8
JournalBiochimica et Biophysica Acta - General Subjects
Volume1861
Issue number11
Publication statusPublished - Nov 2017
Externally publishedYes

Abstract

Background The tripartite efflux pump AcrAB-TolC in E. coli is involved in drug resistance by transporting antibiotics out of the cell. The outer membrane protein TolC can be blocked by various cations, including hexaamminecobalt, thereby TolC represents a potential target for reducing antimicrobial resistance as its blockage may improve efficacy of antibiotics. Methods We utilized single channel electrophysiology measurements for studying TolC conductance in the absence and presence of the known TolC blocker hexaamminecobalt. Association and dissociation constants of hexaamminecobalt were determined using surface plasmon resonance measurements. Minimum inhibitory concentration (MIC) assays in the absence and presence of antibiotics were carried out for investigating the antibacterial effect of hexaamminecobalt and its potential to reduce MICs. Results TolC gating in the absence of any ligand is voltage dependent and asymmetric at high applied voltages. Hexaamminecobalt binds to TolC with high affinity and kinetic data revealed fast association and dissociation rates. Despite potent binding to TolC, hexaamminecobalt does not possess an intrinsic antimicrobial activity against E. coli nor does it reduce MIC values of antibiotics erythromycin and fusidic acid. Conclusions TolC opening can be effectively blocked by small molecules. More potent channel blockers are needed in order to investigate the eligibility of TolC as drug target. General significance TolC, a potentially interesting pharmaceutical target can be addressed by small molecules, blocking the channel. Biophysical characterization of the binding processes will support future identification and optimisation of more potent TolC blockers in order to validate TolC as a pharmaceutical target.

Keywords

    Electrophysiology, Hexaamminecobalt, Surface plasmon resonance, TolC

ASJC Scopus subject areas

Cite this

Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt. / Gilardi, A.; Bhamidimarri, S. P.; Brönstrup, M. et al.
In: Biochimica et Biophysica Acta - General Subjects, Vol. 1861, No. 11, 11.2017, p. 2702-2709.

Research output: Contribution to journalArticleResearchpeer review

Gilardi, A, Bhamidimarri, SP, Brönstrup, M, Bilitewski, U, Marreddy, RKR, Pos, KM, Benier, L, Gribbon, P, Winterhalter, M & Windshügel, B 2017, 'Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt', Biochimica et Biophysica Acta - General Subjects, vol. 1861, no. 11, pp. 2702-2709. https://doi.org/10.1016/j.bbagen.2017.07.014
Gilardi, A., Bhamidimarri, S. P., Brönstrup, M., Bilitewski, U., Marreddy, R. K. R., Pos, K. M., Benier, L., Gribbon, P., Winterhalter, M., & Windshügel, B. (2017). Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt. Biochimica et Biophysica Acta - General Subjects, 1861(11), 2702-2709. https://doi.org/10.1016/j.bbagen.2017.07.014
Gilardi A, Bhamidimarri SP, Brönstrup M, Bilitewski U, Marreddy RKR, Pos KM et al. Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt. Biochimica et Biophysica Acta - General Subjects. 2017 Nov;1861(11):2702-2709. doi: 10.1016/j.bbagen.2017.07.014
Gilardi, A. ; Bhamidimarri, S. P. ; Brönstrup, M. et al. / Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt. In: Biochimica et Biophysica Acta - General Subjects. 2017 ; Vol. 1861, No. 11. pp. 2702-2709.
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title = "Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt",
abstract = "Background The tripartite efflux pump AcrAB-TolC in E. coli is involved in drug resistance by transporting antibiotics out of the cell. The outer membrane protein TolC can be blocked by various cations, including hexaamminecobalt, thereby TolC represents a potential target for reducing antimicrobial resistance as its blockage may improve efficacy of antibiotics. Methods We utilized single channel electrophysiology measurements for studying TolC conductance in the absence and presence of the known TolC blocker hexaamminecobalt. Association and dissociation constants of hexaamminecobalt were determined using surface plasmon resonance measurements. Minimum inhibitory concentration (MIC) assays in the absence and presence of antibiotics were carried out for investigating the antibacterial effect of hexaamminecobalt and its potential to reduce MICs. Results TolC gating in the absence of any ligand is voltage dependent and asymmetric at high applied voltages. Hexaamminecobalt binds to TolC with high affinity and kinetic data revealed fast association and dissociation rates. Despite potent binding to TolC, hexaamminecobalt does not possess an intrinsic antimicrobial activity against E. coli nor does it reduce MIC values of antibiotics erythromycin and fusidic acid. Conclusions TolC opening can be effectively blocked by small molecules. More potent channel blockers are needed in order to investigate the eligibility of TolC as drug target. General significance TolC, a potentially interesting pharmaceutical target can be addressed by small molecules, blocking the channel. Biophysical characterization of the binding processes will support future identification and optimisation of more potent TolC blockers in order to validate TolC as a pharmaceutical target.",
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TY - JOUR

T1 - Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt

AU - Gilardi, A.

AU - Bhamidimarri, S. P.

AU - Brönstrup, M.

AU - Bilitewski, U.

AU - Marreddy, R. K.R.

AU - Pos, K. M.

AU - Benier, L.

AU - Gribbon, P.

AU - Winterhalter, M.

AU - Windshügel, B.

PY - 2017/11

Y1 - 2017/11

N2 - Background The tripartite efflux pump AcrAB-TolC in E. coli is involved in drug resistance by transporting antibiotics out of the cell. The outer membrane protein TolC can be blocked by various cations, including hexaamminecobalt, thereby TolC represents a potential target for reducing antimicrobial resistance as its blockage may improve efficacy of antibiotics. Methods We utilized single channel electrophysiology measurements for studying TolC conductance in the absence and presence of the known TolC blocker hexaamminecobalt. Association and dissociation constants of hexaamminecobalt were determined using surface plasmon resonance measurements. Minimum inhibitory concentration (MIC) assays in the absence and presence of antibiotics were carried out for investigating the antibacterial effect of hexaamminecobalt and its potential to reduce MICs. Results TolC gating in the absence of any ligand is voltage dependent and asymmetric at high applied voltages. Hexaamminecobalt binds to TolC with high affinity and kinetic data revealed fast association and dissociation rates. Despite potent binding to TolC, hexaamminecobalt does not possess an intrinsic antimicrobial activity against E. coli nor does it reduce MIC values of antibiotics erythromycin and fusidic acid. Conclusions TolC opening can be effectively blocked by small molecules. More potent channel blockers are needed in order to investigate the eligibility of TolC as drug target. General significance TolC, a potentially interesting pharmaceutical target can be addressed by small molecules, blocking the channel. Biophysical characterization of the binding processes will support future identification and optimisation of more potent TolC blockers in order to validate TolC as a pharmaceutical target.

AB - Background The tripartite efflux pump AcrAB-TolC in E. coli is involved in drug resistance by transporting antibiotics out of the cell. The outer membrane protein TolC can be blocked by various cations, including hexaamminecobalt, thereby TolC represents a potential target for reducing antimicrobial resistance as its blockage may improve efficacy of antibiotics. Methods We utilized single channel electrophysiology measurements for studying TolC conductance in the absence and presence of the known TolC blocker hexaamminecobalt. Association and dissociation constants of hexaamminecobalt were determined using surface plasmon resonance measurements. Minimum inhibitory concentration (MIC) assays in the absence and presence of antibiotics were carried out for investigating the antibacterial effect of hexaamminecobalt and its potential to reduce MICs. Results TolC gating in the absence of any ligand is voltage dependent and asymmetric at high applied voltages. Hexaamminecobalt binds to TolC with high affinity and kinetic data revealed fast association and dissociation rates. Despite potent binding to TolC, hexaamminecobalt does not possess an intrinsic antimicrobial activity against E. coli nor does it reduce MIC values of antibiotics erythromycin and fusidic acid. Conclusions TolC opening can be effectively blocked by small molecules. More potent channel blockers are needed in order to investigate the eligibility of TolC as drug target. General significance TolC, a potentially interesting pharmaceutical target can be addressed by small molecules, blocking the channel. Biophysical characterization of the binding processes will support future identification and optimisation of more potent TolC blockers in order to validate TolC as a pharmaceutical target.

KW - Electrophysiology

KW - Hexaamminecobalt

KW - Surface plasmon resonance

KW - TolC

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U2 - 10.1016/j.bbagen.2017.07.014

DO - 10.1016/j.bbagen.2017.07.014

M3 - Article

C2 - 28746830

AN - SCOPUS:85026390639

VL - 1861

SP - 2702

EP - 2709

JO - Biochimica et Biophysica Acta - General Subjects

JF - Biochimica et Biophysica Acta - General Subjects

SN - 0304-4165

IS - 11

ER -