title: Study of the betulin molecule in a water environment; ab initio and molecular simulation calculations.
abstract: Ab initio and molecular simulation methods were used in calculations of the neutral individual betulin molecule, and molecular simulations were used to optimize the betulin molecule immersed in various amounts of water. Individual betulin was optimized in different force fields to find the one exhibiting best agreement with ab initio calculations obtained in the Gaussian03 program. Dihedral torsions of active groups of betulin were determined for both procedures, and related calculated structures were compared successfully. The selected force field was used for subsequent optimization of betulin in a water environment, and a conformational search was performed using quench molecular dynamics. The total energies of betulin and its interactions in water bulk were calculated, and the influence of water on betulin structure was investigated.
authors.affiliation: Faculty of Mathematics and Physics, Charles University in Prague, Prague, Czech Republic. pospisil@karlov.mff.cuni.cz
authors.forename: Miroslav
authors.initials: M
authors.lastname: Pospíšil
authors.forename: Petr
authors.initials: P
authors.lastname: Kovář
authors.forename: Robert
authors.initials: R
authors.lastname: Vácha
authors.forename: Michal
authors.initials: M
authors.lastname: Svoboda
mesh_terms: D003198:Computer Simulation; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D014315:Triterpenes / Q000138:chemical synthesis / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D000094062:Betulinic Acid
chemical_list: D014315:Triterpenes; D014867:Water; C002503:betulin; D000094062:Betulinic Acid