RAMAN AND FTIR INTERACTION BETWEEN L-CYSTEINE METHYL ESTER AND DPPC IN ANHYDROUS STATE

J. M. ARIAS; M. E. TUTTOLOMONDO; S. B. DIAZ; A. BEN ALTABEF

Córdoba

Congreso; XLII Congreso Argentino de Biofísica; 2013

UNC

This work is the contribution of a number of studies about the cysteine family (L-cysteine, L-cysteine ethyl ester and L-cysteine methyl ester) to understand lipid membrane interaction. The cysteine family has a thiol group that takes part in a variety of biochemical reactions. The possible formation of weak hydrogen bonds at receptor sites is of considerable interest, as it might contribute to a biological response. The objective this work is understand and analyze the interaction of the complex of L-cysteine methyl ester.HCl (CME) with lyophilized liposomes of dipalmitoylphosphatidylcholine (DPPC) by Raman and infrared (FTIR) spectroscopies. Our results revealed intermolecular interactions between the headgroups of DPPC and CME. These interactions would indicate that the phosphate group of the lipid membrane forms hydrogen bonds probably with S-H groups of CME in replacement of structured water. The Raman analysis shows that the CME has little interaction with the hydrophobic region of DPPC. The intensity ratio analyses show that the density of lateral packing of the acyl chain (I2881/I2846) and the intensity ratio relevant to Gauche-trans rotamers (I1096/I1062) do not have significant changes. The I2933/I2846 intensity ratios show an increase in movement and rotational disorder without an increase of the number of Gauche-trans rotamers.