| Abstract: | The nonbonded portion of a force field for lecithins was characterized by application to the study of the crystal packing geometry and energetics of eight different molecules. The molecules were either lecithin fragments or chosen to isolate particular intermolecular features to test the accuracy of the force field specifically for those interactions. In particular, the hydrocarbon interactions, hydrogen bonding, electrostatics, and phosphate interactions were critiqued. The results support previous findings that indicated that this force field is reasonably accurate for lecithins. For all molecules, a minimum was found near the experimentally determined crystal structure. Using D-glucitol as an example, it is shown that the structural effect of hydrogen bonding is better represented by a nonelectrostatic force-field model than by a purely electrostatic model. Results obtained with glycerylphosphocholine and four smaller organic phosphate molecules suggest that further study of nonbonded interactions of phosphate groups is needed. © John Wiley & Sons, Inc. |
