Solvation of beta-D-glucosamine in water by Monte Carlo method

Abstract

The solvation structure of glucosamine in aqueous solution at 25°C has been investigated using the Metropolis Monte Carlo scheme. The system contains 202 rigid particles, including one glucosamine molecule, which fixed at the center of the cube, and 201 water molecules. An experiment density of 1 g.cm⁻ᵌ of water was used, a periodic side length of 18.26 Å was yielded. A glucosamine-water potential function has been newly developed based on DZP ab initio calculations, while the MCY potential function was employed to describe water-water interactions. The first solvation shell appears at 4.6 Å from the center of glucosamine with the coordination numbers of 7 water molecules. The results indicate clearly that 1 water molecule lies in the ligand’s plane while 2 and 4 water molecules are about 2 - 4 Å above and below the plane, respectively. Among the 7 water molecules, only that binding to ring oxygen atom displays linear H - bond. In addition, second solvation shell with contains 19 water molecules has been also clearly detected.