Location of PRODAN in lipid layer of HDL particle: a Raman study

Abstract

FT Raman spectroscopy has been applied to determine the location of PRODAN within HDL and to investigate its influence on the structure of the particle. The complex spectra of HDL and HDL labeled with PRODAN were divided into three regions according to the wave numbers, and adherent spectra were compared separately. Additionally, recorded spectra of protein and lipid fractions of HDL were used as a support for the assignment of particular vibrations in intact particles. In high frequency region, the shift in vibrational frequencies of CH 3 groups but almost negligible shift of CH 2 groups suggests that PRODAN is situated at the water/lipid interface in the vicinity of the protein. The statement is supported by the observed influence of PRODAN on particular lipid vibrations of phospholipids head-groups.In the fingerprint region, the influence of PRODAN is observed as the slight change in -strand secondary structure of apolipoprotein and strongly reduced vibrations of the acyl chain in lipids. That additionally confirms that PRODAN mainly interacts with the lipid domain of the particle. In the low frequency region, the lack of change in Tyr Fermi resonance doublet and only slight differences in the pattern of CS and SS stretching vibrations in labeled HDL confirms that PRODAN has no influence on structure of apolipoprotein embeddd in lipid domain. The main conclusions drawn from the vibrational spectra of HDL with and without PRODAN clearly confirm that PRODAN induces negligible changes in HDL structure and hence is reliable fluorescent label for the structural analysis.

Molecular Dynamics Investigations of PRODAN in a DLPC Bilayer

“…Fluorescence studies varying the phospholipid concentration have also been interpreted assuming the PRODAN molecule arranged in both the polar and the less polar regions of the bilayer. 14 The amphiphilic behavior of the PRODAN molecule has been corroborated by infrared 15 and Raman 16 studies. On the basis of pressure dependent experimental fluorescence studies on giant multilamelar vesicles containing lipids with phosphatidylcholine headgroups, the PRODAN molecule has been localized not only close to the glycerol backbone but also in the hydrophilic part of the membrane.…”

“…Fluorescence studies varying the phospholipid concentration have also been interpreted assuming the PRODAN molecule arranged in both the polar and the less polar regions of the bilayer . The amphiphilic behavior of the PRODAN molecule has been corroborated by infrared and Raman studies.…”

Optical characterization of Prodan aggregates in water medium

“…Since it was designed by Weber and coworker, 8 Prodan (2-dimethylamino-6-propionylnaphthalene) has been used as a fluorescent probe to study several biologically relevant systems, such as membranes, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] proteins, 8,[25][26][27][28] and others. [29][30][31][32] Although widely used and studied, mostly as a lipid membrane probe, Prodan properties in different environments, both in the fundamental and excited states, are still controversial.…”

Comparative analysis of lipotoxicity induced by endocrine, pharmacological, and innate immune stimuli in rat basophilic leukemia cells

“…Since these data suggest heterogeneity in terms of the accumulation of lipophilic dyes in RBL2H3 LB, a panel of lipophilic dyes was screened for ability to stain insulin-induced structures in these cells (Figures 4B-4F). These dyes included the cholesterol stain filipin, the Prodan/Laurdan lipophiles, DPH, and nuclear dyes DAPI or 7-AAD (Krasnowska et al, 1998; Bagatolli et al, 2000; Krilov et al, 2008; Ranall et al, 2011; Storey et al, 2011). …”