A study of the influence of Na[superscript +] on the conformation of glycine zwitterion in aqueous solution

Abstract

The interaction of glycine zwitterion and water is calculated using ab initio method with minimized GLO basis set. The first hydration shell of glycine zwitterion is predicted to compose of five water molecules. The influence of the first hydration to the internal rotation of glycine zwitterion is studied and the energy optimized pathway is compared with that of isolated molecule. The investigation of glycine zwitterion-Na[superscript +] complex in water provides that the two coordinated water of aquo complex of Na[superscript +] are dehydrated and replaced by glycine zwitterion. Thus the formula of the complex is described as [ Na(gly) (H[subscript 2]O[subscript 4] ] [superscript +]. The Na[superscript +]-OH[subscript 2] distances in the complex are 2.20 A. The effect of . Na[superscript +] and its coordinated water on the first hydration shell of glycine zwitterion are discussed on the basis of both charge distribution and stabilization energies.