title: Refinement of the AMBER force field for nucleic acids: improving the description of alpha/gamma conformers.
abstract: We present here the parmbsc0 force field, a refinement of the AMBER parm99 force field, where emphasis has been made on the correct representation of the alpha/gamma concerted rotation in nucleic acids (NAs). The modified force field corrects overpopulations of the alpha/gamma = (g+,t) backbone that were seen in long (more than 10 ns) simulations with previous AMBER parameter sets (parm94-99). The force field has been derived by fitting to high-level quantum mechanical data and verified by comparison with very high-level quantum mechanical calculations and by a very extensive comparison between simulations and experimental data. The set of validation simulations includes two of the longest trajectories published to date for the DNA duplex (200 ns each) and the largest variety of NA structures studied to date (15 different NA families and 97 individual structures). The total simulation time used to validate the force field includes near 1 mus of state-of-the-art molecular dynamics simulations in aqueous solution.
authors.affiliation: Molecular Modeling and Bioinformatics Unit, Institut de Recerca Biomèdica & Instituto Nacional de Bioinformática, Parc Científic de Barcelona, Barcelona 08028, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pérez
authors.forename: Iván
authors.initials: I
authors.lastname: Marchán
authors.forename: Daniel
authors.initials: D
authors.lastname: Svozil
authors.forename: Jiri
authors.initials: J
authors.lastname: Sponer
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Cheatham
authors.forename: Charles A
authors.initials: CA
authors.lastname: Laughton
authors.forename: Modesto
authors.initials: M
authors.lastname: Orozco
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry*
chemical_list: D012313:RNA; D004247:DNA