Effect of progesterone on DPPC membrane: Evidence for lateral phase separation and inverse action in lipid dynamics

Korkmaz, F
Severcan, Feride
Interactions of progesterone with zwitterionic dipalmitoyl phosphatidylcholine (DPPC) triultilamellar liposomes were investigated as a function of temperature and progesterone concentration by using three non-invasive techniques namely Fourier transform infrared spectroscopy, turbidity at 440 nm, and differential scanning calorimetry. The results reveal that progesterone changes the physical properties of DPPC bilayers by decreasing the main phase-transition temperature, abolishing the pre-transition, broadening the phase-transition profile, disordering the system both in gel and liquid crystalline phase, increasing the dynamics at low concentrations whereas stabilizing the membrane at high concentrations, and inducing phase separation. Progesterone does not change the hydration of the C=O groups, while it strengthens the hydrogen bonding between the PO (2) over bar groups of lipids and the water molecules around. (c) 2005 Elsevier Inc. All rights reserved.


IR and turbidity studies of vitamin E-cholesterol-phospholipid membrane interactions
Severcan, Feride; Kazanci, Nadide; Baykal, Ülkü; Süzer, Şefik (Portland Press Ltd., 1995-8-1)
Binary and tertiary mixture of α-tocophenol, cholesterol and dimyristoylphosphatidylcholine in the form of multilamellar liposomes were investigated by Fourier Transform Infrared and visible spectroscopy. Results of the FTIR and turbidity experiments indicate that α T decreases or diminishes the effect of cholesterol on the frequency and the bandwidth of the C-H stretching, CH2 scissoring and C=O stretching bands in FTIR spectra and the turbidity measurements (recorded as absorbance values at 440 nm) in pho...
Using artificially generated spectral data to improve protein secondary structure prediction from Fourier transform infrared spectra of proteins
Severcan, M; Haris, PI; Severcan, Feride (Elsevier BV, 2004-09-15)
Secondary structures of proteins have been predicted using neural networks from their Fourier transform infrared spectra. To improve the generalization ability of the neural networks, the training data set has been artificially increased by linear interpolation. The leave-one-out approach has been used to demonstrate the applicability of the method. Bayesian regularization has been used to train the neural networks and the predictions have been further improved by the maximum-likelihood estimation method. T...
Effect of gramicidin S on the dipalmitoylphosphatidyl-glycerol thermotropic phase transition in DPPG/GS systems: A mathematical approach
Stan, Cristina; Cristescu, C. P.; Severcan, Feride; Dorohoi, Dana (Informa UK Limited, 2006-01-01)
We present a mathematical approach to the experimental data recorded via Fourier transform-infrared spectroscopy regarding the influence of the concentration of the antimicrobial peptide gramicidin S (GS) on the thermotropic phase transition of the dipalmitoylphosphatidyl-glycerol (DPPG) lipid bilayer membrane in DPPG/GS systems. The model is based on the influence of the GS concentration on the parameters of a nonlinear damped oscillator, which models the CH2 symmetric stretching band.
Interactions of tamoxifen with distearoyl phosphatidylcholine multilamellar vesicles: FTIR and DSC studies
Bilge, Duygu; ŞAHİN, İPEK; KAZANCI, NADİDE; Severcan, Feride (Elsevier BV, 2014-09-15)
Interactions of a non-steroidal antiestrogen drug, tamoxifen (TAM), with distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) multilamellar liposomes (MLVs) were investigated as a function of drug concentration (1-15 mol%) by using two noninvasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy results show that increasing TAM concentrations (except 1 mol%) increased the wavenumbers of the CH2 stretching modes, implying an disord...
Effect of thermal treatment on secondary structure and conformational change of mushroom polyphenol oxidase (PPO) as food quality related enzyme: A FTIR study
Baltacioglu, Hande; Bayındırlı, Alev; Severcan, Mete; Severcan, Feride (2015-11-15)
In order to understand the conformational changes of polyphenol oxidase (PPO), which is a food quality related enzyme, after thermal treatment, secondary structure changes of the enzyme were analyzed by using Fourier Transform Infrared (FTIR) spectroscopy and compared with the change in enzyme activity in the temperature range of 25-80 degrees C. Fourier self-deconvolution, neural network (NN) and curve-fitting analysis were applied to the amide I band of FTIR spectra for detail analysis of secondary struct...
Citation Formats
F. Korkmaz and F. Severcan, “Effect of progesterone on DPPC membrane: Evidence for lateral phase separation and inverse action in lipid dynamics,” ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, pp. 141–147, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57281.