Reorganization of Hydration Water of DPPC Multilamellar Vesicles Induced by l -Cysteine Interaction

DÍAZ, SONIA B.; TUTTOLOMONDO, MARÍA E.; TUTTOLOMONDO, MARÍA E.; ARIAS, JUAN M.; BEN ALTABEF, AIDA; ARIAS, JUAN M.; BEN ALTABEF, AIDA; DÍAZ, SONIA B.

JOURNAL OF PHYSICAL CHEMISTRY B - (Print)

AMER CHEMICAL SOC

Año: 2018 p. 5193 - 5204

1520-6106

Theaim of this work is to analyze the consequences of water redistribution on thestructure and stability of phospholipid bilayers induced by Cysteine (Cys).This interaction is studied with dipalmitoylphosphatidylcholine (DPPC)multilamellar vesicles, in gel (30 ºC) and liquid crystalline (50 ºC) state;experimental studies were performed by means of Infrared Spectroscopy (FTIR),Raman Spectroscopy and Differential Scanning Calorimetry (DSC).The polar head sites of the lipidmolecules to which water can bind are identified by competition with compoundsthat form hydrogen bonds such as Cys. FTIR resultsrevealed that there is a Cys interaction with the phospholipid head groups ingel and liquid crystalline phases. Raman spectra were measured in gel state. Theywere dominated by vibrations of the fatty acyl chains, with superposition of afew bands from the head group, and clearly showed that the S-H stretching band ofCys shifted to lower frequencies with a decrease in its force constant. DSC disclosed an overview of the behaviorof the multilamellar vesicles in the work temperature range (30 °C to 50 °C)and showed how the increase of the molar ratios modified the environment of thepolar head and the hydrocarbon chains. A loss of the pre transition (TP)and an increase in the value of temperature of main transition (Tm)with increasing Cys:DPPC molar ratio were observed.