Fluorescence quenching of gramicidin D in model membranes by halothane

2007 ◽  
Vol 85 (7-8) ◽  
pp. 513-519 ◽  
Author(s):  
Anna Carnini ◽  
Trinh T Nguyen ◽  
David T Cramb
Keyword(s):  
Fluorescence Quenching ◽  
Ion Channel ◽  
Lipid Bilayer ◽  
Sodium Dodecyl ◽  
Inhaled Anesthetics ◽  
Sds Micelles ◽  
Neuronal Membranes ◽  
Gramicidin D ◽  
Tryptophan Residues ◽  
Anesthetic Action

Inhaled anesthetics were introduced in surgery over a century ago. To this day, the molecular mechanism of anesthetic action remains largely unknown. However, ion-channels of neuronal membranes are believed to be the most- likely molecular targets of inhaled anesthetics. In the study presented here, we investigated the interaction of a simplified ion-channel system, gramicidin, with halothane, a small haloalkane inhaled anesthetic in various environments. Fluorescence-quenching experiments of gramicidin D in dioleoylphosphatidylcholine (DOPC) large unilamellar vesicles (LUVS) have shown that halothane can directly interact with the ion channel (KSV = 66 M–1). Halothane quenched the fluorescence from tryptophan residues located at the lipid bilayer – aqueous interfaces as well as those tryptophans located deeper in the bilayer. Quenching data from gramicidin D in sodium dodecyl sulfide (SDS) micelles revealed that the tryptophan residues located at the micelle–solvent interface were preferentially quenched by halothane (KSV = 22 M–1). In 1-octanol, fluorescence quenching was observed, but with a lower KSV value (KSV = 6 M–1) than in DOPC LUVS and SDS micelles. Taken together, these results indicate that halothane interactions with gramicidin, mediated by a lipid bilayer, are the strongest, and that the mechanism of anesthetic action may also be lipid-mediated.

Voltage-induced gating of the mechanosensitive MscL ion channel reconstituted in a tethered lipid bilayer membrane

2008 ◽  
Vol 23 (6) ◽  
pp. 919-923 ◽  
Author(s):  
Martin Andersson ◽  
George Okeyo ◽  
Danyell Wilson ◽  
Henk Keizer ◽  
Paul Moe ◽  
...  
Keyword(s):  
Ion Channel ◽  
Lipid Bilayer ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane

The interaction of bovine milk caseins with the detergent sodium dodecyl sulphate. II. The effect of detergent binding on spectral properties of caseins

1970 ◽  
Vol 37 (2) ◽  
pp. 259-267 ◽  
Author(s):  
G. C. Cheeseman ◽  
Dorothy J. Knight
Keyword(s):  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Bovine Milk ◽  
Difference Spectrum ◽  
Temperature Dependent ◽  
Difference Spectra ◽  
Negative Change ◽  
Tryptophan Residues ◽  
Hydrophobic Binding ◽  
The Difference

SummaryThe dissociation of casein aggregates by the detergent sodium dodecyl sulphate (SDS) gave rise to difference spectra and these spectra were characteristic for each of the different types of casein. Increase in absorption by the chromophore groups, tyrosine and tryptophan, when αs1- and β-casein aggregates were dissociated indicated binding of the detergent at regions of the molecule containing these residues. A decrease in absorption when κ-casein was dissociated indicated that the tyrosine and tryptophan residues were not in the region of the molecule to which the detergent was bound and that in the κ-casein aggregate these residues were in a more hydrophobic environment. Peaks on the difference spectra were obtained at 280 and 288 nm for αs1-casein and 284 and 291 nm for β-casein and troughs at 278 and 286 nm for κ-casein. The difference spectrum reached a maximum value when the αsl- and β-casein aggregates were dissociated and the further binding of SDS did not alter this value. The large negative change in the difference spectrum of κ-casein did not occur until after most of the aggregates were dissociated and did not reach a maximum until binding with SDS was complete. The value obtained for ΔOD was found to be temperature-dependent for β-casein-SDS interaction, but not for αs1- and κ-casein. Changes in spectra were also observed when αs1- and κ-casein interacted to form aggregates. The data obtained confirmed the importance of hydrophobic binding in casein aggregate formation and indicated the possible involvement of tyrosine and tryptophan residues in this binding.

Automatable lipid bilayer formation for ion channel studies

2008 ◽  
Author(s):  
Jason L. Poulos ◽  
Hyunwoo Bang ◽  
Tae-Joon Jeon ◽  
Jacob J. Schmidt
Keyword(s):  
Ion Channel ◽  
Lipid Bilayer ◽  
Bilayer Formation

scholarly journals Is Lipid Bilayer Binding a Common Property of Inhibitor Cysteine Knot Ion-Channel Blockers?

2007 ◽  
Vol 93 (4) ◽  
pp. L20-L22 ◽  
Author(s):  
Yevgen O. Posokhov ◽  
Philip A. Gottlieb ◽  
Michael J. Morales ◽  
Frederick Sachs ◽  
Alexey S. Ladokhin
Keyword(s):  
Ion Channel ◽  
Lipid Bilayer ◽  
Common Property ◽  
Channel Blockers ◽  
Ion Channel Blockers

Automated lipid bilayer and ion channel measurement platform

2011 ◽  
Vol 26 (5) ◽  
pp. 2651-2654 ◽  
Author(s):  
Tanuj Thapliyal ◽  
Jason L. Poulos ◽  
Jacob J. Schmidt
Keyword(s):  
Ion Channel ◽  
Lipid Bilayer ◽  
Channel Measurement

scholarly journals Aggregation equilibria of tyrosinase of Harding-Passey mouse melanoma

1985 ◽  
Vol 228 (1) ◽  
pp. 95-101 ◽  
Author(s):  
J C Garcia-Borron ◽  
F Solano ◽  
J L Iborra ◽  
J A Lozano
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Permeation Chromatography ◽  
Aqueous Environment ◽  
Fluorescence Studies ◽  
Mouse Melanoma ◽  
Low Protein ◽  
Tryptophan Residues ◽  
Sample Dilution

The purification of two isoenzymes of tyrosinase has been carried out in Harding-Passey mouse melanoma. One is found in the cytosol and the other one bound to melanosomes. Both migrate as single bands on sodium dodecyl sulphate/polyacrylamide gels, having an apparent Mr of 58 000. Solubilized particulate tyrosinase showed an aggregation equilibrium involving a monomer, tetramer, octamer and a high-Mr micellar form with Brij 35, the solubilizing agent. H.p.l.c. studies indicated a interconversion between those species, the monomer contribution increasing with the sample dilution. The tetramer and the octamer probably represent the predominant forms in vivo. Soluble tyrosinase showed a simpler aggregation equilibrium, involving two forms, monomer and tetramer, with the same interconversion pattern. Fluorescence studies suggested that tryptophan residues were exposed to the aqueous environment when tyrosinase was dissociated by dilution. Tyrosinase shows a tendency to aggregate, at low protein concentration, and a resistance to dissociation by urea or SDS so remarkable that gel-permeation chromatography in 4M-urea does not affect the equilibrium, and the band obtained on SDS/polyacrylamide-gel electrophoresis is a dimer.

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