On the differential hydration of various forms of glycine in diluted aqueous solutions: a Monte Carlo study

Biljana Bujaroska, Kiro Stojanoski, Ljupco Pejov


Rigid-body Monte Carlo simulations were carried out to study the differential hydration of zwitterionic and neutral forms of glycine in water. To account for the solute polarization by the rather polar liquid environment, initial geometries were chosen as minima on the MP2/aug-cc-pVTZ potential energy surfaces of neutral and zwitterionic glycine continuously solvated by water, implementing the polarizable continuum model (PCM) within the integral equation formalism (IEFPCM). The dynamically changing hydrogen bonding network between the solute and solvent molecules was analyzed imposing distance, energy and angular distribution-based criteria. It was found that, on average, the zwitterionic form of glycine acts as an acceptor of 4.53 hydrogen bonds, while it plays the role of a proton donor in (on average) 2.73 hydrogen bonds with the solvent water molecules. In particular, we have found out that 2.73 solvent water molecules are involved in hydrogen bonding interaction with the ammonium group, acting as proton-acceptors. This is in excellent agreement with the recent experimental neutron diffraction studies, which have indicated that 3.0 water molecules reside in the vicinity of the NH3+ group of aqueous zwitterionic glycine. Neutral form of aqueous glycine, on the other hand, on average donates protons in 1.63 hydrogen bonds with the solvent water molecules, while at the same time it accepts 2.53 hydrogen bonds from the solvent molecules. The greater charge polarization in the zwitterionic form thus makes it much more exposed to hydrogen bonding interaction in polar medium such as water, which is certainly the main reason of the larger stability of this form of glycine in condensed media.


Glycine; neutral and zwitterion; Monte Carlo simulations; hydration of bio-molecules; hydrogen bonding in liquids; differential hydration; polarizable contin-uum model;

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T. Wyttenbach, M. T. Bowers, Hydration of biomolecules, Chem. Phys. Lett. 480, 1-16 (2009).

M. G. Campo, Molecular dynamics simulation of glycine zwitterions in aqueous solu-tion, J. Chem. Phys. 125, 114511 (2006).

J. Sun, D. Bousquet, H. Forbert, D. Marx, Glycine in aqueous solution: solvation shells, interfacial water, and vibrational spectroscopy from ab initio molecular dynam-ics, J. Chem. Phys. 133, 114508 (2010).

A. White, S. Jiang, Local and bulk hydration of zwitterionic glycine and its analogues through molecular simulations, J. Phys. Chem. B 115, 660-667 (2011).

K. Leung, S. B. Rempe, Ab initio molecular dynamics study of glycine intramolecular proton transfer in water, J. Chem. Phys. 122, 184506 (2005).

N. Vyas, A. K. Ojha, A. Materny, Simulation of the Raman spectra of zwitterionic glycine + nH2O (n = 1, 2, …, 5) by means of DFT calculations and comparison to the experimentally observed Raman spectra of glycine in aqueous medium, Vibrat. Spec-trosc. 55, 69-76 (2011).

T. Yoshikawa, H. Motegi, A. Kakizaki, T. Takayanagi, M. Shiga, M. Tachikawa, Path-integral molecular dynamics simulations of glycine•(H2O)n (n = 1-7) clusters on semi-empirical PM6 potential energy surfaces, Chem. Phys. 365, 60-68 (2009).

K. T. Lee, K. Y. Han, I. Oh, S. K. Kim, Barierless pathways in the neutral-zwitterion transition of amino-acid: Glycine-(H2O)9, Chem. Phys. Lett. 495, 14-16 (2010).

F. Lelj, C. Adamo, V. Barone, Role of Hartree-Fock exchange in density functional theory. Some aspects of the conformational potential energy surface of glycine in the gas phase, Chem. Phys. Lett. 230, 189-195 (1994).

L. F. Pacios, P. C. Gómez, Atomic charges in conformers of gaseous glycine, J.Mol. Struct. (THEOCHEM) 544, 237-251 (2001).

P. Selvarengan, P. Kolandaivel, Potential energy surface study of glycine, alanine and their zwitterionic forms, J.Mol. Struct. (THEOCHEM) 671, 77-86 (2004).

M. Kieninger, S. Suhai, O. N. Ventura, Glycine conformations: gradient-corrected DFT-studies, J.Mol. Struct. (THEOCHEM) 433, 193-201 (1998).

R. A. Cormanich, L. C. Ducati, R. Rittner, Are hydrogen bonds responsible for glycine conformational preferences?, Chem. Phys. 387, 85-91 (2011).

A. G. Császár, Conformers of gaseous glycine, J. Am. Chem. Soc. 114, 9568-9575 (1992).

P. Palla, C. Petrongolo, J. Tomasi, Internal rotation potential energy for the glycine molecule in its zwitterionic and neutral form. A comparison among several methods, J. Phys. Chem. 84, 435-442 (1980).

R. Bonaccorsi, P. Palla, J. Tomasi, Conformational energy of glycine in aqueous solu-tions and relative stability of the zwitterionic and neutral forms. An ab initio study, J. Am. Chem. Soc. 106, 1945-1950 (1984).

M. T. Parsons, Y. Koga, Hydration number of glycine in aqueous solutions: An ex-perimental estimate, J. Chem. Phys. 123, 234504 (2005).

T. Watanabe, K. Hashimoto, H. Takase, O. Kikuchi, J. Mol. Struct. (THEOCHEM) 397, 113-119 (1997).

C. Alagona, C. Ghio, P. A. Kollman, J. Mol. Struct. (THEOCHEM) 166, 385-392 (1988).

C. Alagona, C. Ghio, J. Mol. Liq. 47, 139-160 (1990).

Yu. I. Khurgin, V. A. Kudryashova, V. A. Zavizion, Study of intermolecular interac-tions in aqueous solutions by millimeter spectroscopy, Russ. Chem. Bull. 46, 1248-1250 (1997).

M. Tschapek, C. Wasowski, The hydration of a zwitterion, glycine, as a function of pH, Biochim. Biophys. Acta 582, 548-550 (1979).

C. Espinoza, J. Szczepanski, M. Vala, N. C. Polfer, Glycine and its hydrated com-plexes: A matrix isolation infrared study, J. Phys. Chem. A 114, 5919-5927 (2010).

B. Yogeswari, R. Kanakaraju, A. Abiram, P. Kolandaivel, Molecular dynamics and quantum chemical studies on incremental solvation of glycine, Comp. Theor. Chem. 967, 81-92 (2011).

R. M. Balabin, The first step in glycine solvation: The glycine-water complex, J. Phys. Chem. B 114, 15075-15078 (2010).

J. Chang, A. M. Lenhoff, S. I. Sandler, Solvation free energy of amino acids and side-chain analogues, J. Phys. Chem. B 111, 2098-2106 (2007).

C.-M. Liegener, A. K. Bakhshi, R. Chen, J. Ladik, Theoretical Auger spectra of the glycine ion in solution, J. Chem. Phys. 86, 6039-6045 (1987).

J. Tomasi, B. Mennucci, R. Cammi, Quantum mechanical continuum solvation mod-els, Chem. Rev. 105, 2999-3093 (2005).

C. Peng, P. Y. Ayala, H. B. Schlegel, M. J. Frisch, Using redundant internal coordi-nates to optimize equilibrium geometries and transition states, J. Comp. Chem. 17, 49-56 (1996).

K. Coutinho and S. Canuto, DICE: A Monte Carlo program for molecular liquid simu-lation, University of São Paulo, Brazil, 1997.

H. J. C. Berendsen, J. P. M. Postma, W. F. van Gunsteren, J. Hermans, Intermolecular Forces, edited by B. Pullmam (Reidel, Dordrecht, 1981), p.331.

C. M. Breneman, K. B. Wiberg, Determining atom-centered monopoles from molecu-lar electrostatic potentials - the need for high sampling density in formamide confor-mational-analysis, J. Comp. Chem. 11, 361-73 (1990).

W. L. Jorgensen, D. S. Maxwell, J. Tirado-Rives, Development and testing of the OPLS all-atom force field on conformational energetic and properties of organic liq-uids, J. Am. Chem. Soc. 118, 11225-11236 (1996).

DOI: http://dx.doi.org/10.20450/mjcce.2012.11


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