Molecular dynamics simulations of polarizable DNA in crystal environment

摘要

We have investigated the role of the electrostatic description and cell environment in molecular dynamics (MD) simulations of DNA. Multiple unrestrained MD simulations of the DNA duplex d(CCAACGTTGG), have been carried out using two different force fields: a traditional description based on atomic point charges and a polarizable force field. For the time scales probed, and given the "right" distribution of divalent ions, the latter performs better than the nonpolarizable force field. In particular, by imposing the experimental unit cell environment, an initial configuration with ideal B-DNA duplexes in the unit cell acquires sequence-dependent features that very closely resemble the crystallographic ones. Simultaneously, the all-atom root-mean-square coordinates deviation (RMSD) with respect to the crystallographic structure is seen to decay. At later times, the polarizable force field is able to maintain this lower RMSD, while the nonpolarizable force field starts to drift away. (c) 2006 Wiley Periodicals, Inc.