This project focuses on the study of membranes, proteins and carbohydrates by molecular dynamics computer simulation. Force field (FF) development continued for three classes of compounds: lipids, carbohydrates, and ethers. All involved extensive ab initio calculations on small model compounds, followed by extensive molecular dynamics simulations (MD) on the target systems to ensure that a variety of target data were reproduced. The CHARMM carbohydrate FF was extended to disaccharides (the monosaccaharide was completed last year). This enables simulations of numerous polysaccharides, though links to 5 membered rings and some functional groups still need to be incorporated. The 3D-IPS/DFFT method developed by Wu and Brooks (of LCP) was demonstrated to be highly accurate for liquid/liquid and liquid/vapor interfaces, and lipid bilayers and monolayers. Analysis of results from bilayers and monolayers indicated that the large bilayer surface tension arising from the C27r lipid FF is incorrect. This paved the way for a revised lipid FF with substantially lower surface tensions. The new lipid FF, C36, will be submitted for publication shortly, and is already in use by a number of research groups. A coarse-grained (CG) model for polyethylene oxide and polyethylene glycol was developed using simulations from the all-atom model developed last year. Simulations of 9, 18, 27, 36, 44, 67, 76, 90, 112, 135, and 158-mers of the CG PEO (442
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