HYDRATION OF PHOSPHOCOLAMINE AND ION PHOSPHOENOLPIRUVATE IN AQUEOUS SOLUTIONS

BRANDÁN, S. A.; DÍAZ, S. B.; DISALVO, E. A.; BEN ALTABEF, A.

Buenos Aires, Argentina

Congreso; International Workshop on Infrared Spectroscopy; 2007

U. de Buenos Aires

International Workshop on Infrared Spectroscopy Applied to Biological and Biomimetic Systems, Buenos Aires, Noviembre, 2007 HYDRATION OF PHOSPHOCOLAMINE AND ION PHOSPHOENOLPIRUVATE IN AQUEOUS SOLUTIONS Brandán, S. A1, Díaz, S. B1., Disalvo, E. A2. and Ben Altabef, A1. 1Instituto de Química Física. Facultad de Bioquímica, Química y Farmacia. Universidad Nacional de Tucumán. San Lorenzo 456. T4000CAN S. M. de  Tucumán. R.  Argentina. Fax: +54-381-4248169; TEL.: +54-381-4311044 2Laboratorio de Fisicoquímica de Membranas Lipídicas. Facultad de Farmacia y Bioquímica. Universidad de Buenos Aires. Junín 956 2°P. (1113) Buenos Aires. R. Argentina. brandansa@yahoo.com.ar Abstract. B3LYP/6-31G* and 6-311++G** calculations have been carried out to study the hydration of phosphocholamine and phosphoenolpiruvate ion in aqueous solutions. Optimised geometries and relative stabilities for the two compounds have been calculated considering the interaction with one, two, three, four and five discrete water molecules and taking the solvent effect into account by using the self-consistent reaction field theory (Onsager [1] and PCM methods [2]). The role of specific and bulk contributions of solvent effect on the observable properties of phosphocholamine and phosphoenolpiruvate ion compounds are analysed. Good agreement between theoretical and available experimental results of harmonic vibration frequencies is found. Significant effects on the geometrical and vibrational frequencies are found for the phosphate compounds studied [3, 4]. The results presented here provide a first step towards understanding hydration of the phosphate group as a hydration sensor in lipid bilayers. References 1.          M. W. Wong, M. J. Frisch, K. B. Wiberg, J. Am. Chem. Soc., 113 (1991) 4776. 2.          J. Tomasi, M. Persico, Chem. Rev., 94  (1994) 2027. 3          S. A. Brandán, S. B. Díaz, J. J. López González, E. A. Disalvo and A. Ben Altabef, Spectrochim. Acta. Part A 66 (2007) 884-897. 4          S. A. Brandán, S. B. Díaz, R. Cobos Picot, E. A. Disalvo and A. Ben Altabef, Spectrochim. Acta. Part A 66 (2007) 1152-1164. ·         This work was founded with grants from CIUNT (Consejo de Investigaciones Universidad Nacional de Tucumán), CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas) and ANPCYT (Agencia Nacional de promoción Científica y tecnológica) PICT 0324/3.