Details
| Original language | English |
|---|---|
| Pages (from-to) | 2702-2709 |
| Number of pages | 8 |
| Journal | Biochimica et Biophysica Acta - General Subjects |
| Volume | 1861 |
| Issue number | 11 |
| Publication status | Published - Nov 2017 |
| Externally published | Yes |
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
- Biochemistry, Genetics and Molecular Biology(all)
- Biophysics
- Biochemistry, Genetics and Molecular Biology(all)
- Biochemistry
- Biochemistry, Genetics and Molecular Biology(all)
- Molecular Biology
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In: Biochimica et Biophysica Acta - General Subjects, Vol. 1861, No. 11, 11.2017, p. 2702-2709.
Research output: Contribution to journal › Article › Research › peer review
}
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
UR - http://www.scopus.com/inward/record.url?scp=85026390639&partnerID=8YFLogxK
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 -