Modulation of hydration by L-Proline at the interphase of model lipid membranes under hydric stress conditions

VILLALBA, ARACELLI; ROSA ANTONIO SEBASTIÁN; DISALVO EDGARDO ANIBAL; FRIAS MARÍA DE LOS ANGELES

Cordoba

Congreso; LI Reunión Anual de la Sociedad Argentina de Biofísica; 2023

Sociedad Argentina de Biofísica

Water is a structural component of biological membranes, whose thermodynamic properties at the interface are relevant to define the structural parameters of the bilayer. Various physical and chemical factors can modify the hydration water with the consequent effect on the properties of the membrane.L-Proline (L-Pro) is an amino acid, with hydrophobic characteristics, synthesized by some plants during periods of drought. L-Pro plays a highly beneficial role in plants exposed to different abiotic stress conditions, gathering at certain plant tissues and maintaining the cellular membrane integrity under these conditions.The aim of this work is to study the effect of L-Proline on the hydration of the interphase of DMPC model membranes, using infrared spectroscopy (FTIR-ATR), at different temperatures under controlled relative humidity conditions.In order to quantify the system’s hydration degree, the relative water content was analyzed following the area ratio between the water stretching band (3000 – 3800cm-1) and the bands corresponding to methyl and methylene stretching groups. The behavior of the bands of the methylene (-CH2), carbonyl (-CO) and phosphate (PO2-) groups was analyzed in relation to the relative water content and with respect to the variation of the water content in the system.The results show an increase in the water content in the system and a decrease of the transition temperature, compared to the control under the same conditions, in presence of L-Proline in a 1:1 ratio, under hydric stress conditions.It can be concluded that L-Proline modulates the content and availability of water in the membrane, increasing its hydration state. This effect of L-Proline on the DMPC membrane would be the responsible mechanism of protection that the amino-acid exerts on the membrane under stress, bringing its hydration degree closer to that of a membrane without stress. This would allow to keep certain physiological functions active in the cell in hydric stress conditions