| Autor: |
Turina AV; Instituto de Investigaciones Biológicas y Tecnológicas, IIByT, (CONICET- UNC), Cátedra de Química Biológica, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba , Av. Vélez Sarsfield 1611, 5016 Córdoba, Argentina., Clop PD, Perillo MA |
| Jazyk: |
angličtina |
| Zdroj: |
Langmuir : the ACS journal of surfaces and colloids [Langmuir] 2015 Feb 10; Vol. 31 (5), pp. 1792-801. Date of Electronic Publication: 2015 Jan 27. |
| DOI: |
10.1021/la5042986 |
| Abstrakt: |
In this work we used Langmuir-Blodgett films (LB) as model membranes to study the effect of molecular packing on the flunitrazepam (FNZ) accessibility to the binding sites at the GABAA receptor (GABAA-R). Ligand binding data were correlated with film topography analysis by atomic force microscopy images (AFM) and SDS-PAGE. Langmuir films (LF) were prepared by the spreading of synaptosomal membranes (SM) from bovine brain cortex at the air-water interface. LBs were obtained by the transference, at 15 or 35 mN/m constant surface pressure (π), of one (LB15/1c and LB35/1c) or two (LB35/2c) LFs to a film-free hydrophobic alkylated substrate (CONglass). Transference was performed in a serial manner, which allowed the accumulation of a great number of samples. SDS-PAGE clearly showed a 55 kDa band characteristic of GABAA-R subunits. Detrended fluctuation analysis of topographic data from AFM images exhibited a single slope value (self-similarity parameter α) in CONglass and a discontinuous slope change in the α value at an autocorrelation length of ∼100 nm in all LB samples, supporting the LF transference to the substrate. AFM images of CONglass and LB15/1c exhibited roughness and average heights that were similar between measurements and significantly lower than those of LB35/1c and LB35/2c, suggesting that the substrate coverage in the latter was more stable than in LB15/1c. While [(3)H]FNZ binding in LB15/1c did not reach saturation, in LB35/1c the binding kinetics became sigmoid with a binding affinity lower than in the SM suspension. Our results highlight the π dependence of both binding and topological data and call to mind the receptor mechanosensitivity. Thus, LB films provide a tool for bionanosensing GABAA-R ligand binding as well as GABAA-R activity modulation induced by the environmental supramolecular organization. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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