title: Sucrose in aqueous solution revisited, Part 2: adaptively biased molecular dynamics simulations and computational analysis of NMR relaxation.
abstract: We report 100 ns molecular dynamics simulations, at various temperatures, of sucrose in water (with concentrations of sucrose ranging from 0.02 to 4M), and in a 7:3 water-DMSO mixture. Convergence of the resulting conformational ensembles was checked using adaptive-biased simulations along the glycosidic Φ and ψ torsion angles. NMR relaxation parameters, including longitudinal (R₁) and transverse (R₂) relaxation rates, nuclear Overhauser enhancements (NOE), and generalized order parameter (S²) were computed from the resulting time-correlation functions. The amplitude and time scales of molecular motions change with temperature and concentration in ways that track closely with experimental results, and are consistent with a model in which sucrose conformational fluctuations are limited (with 80-90% of the conformations having ϕ-ψ values within 20° of an average conformation), but with some important differences in conformation between pure water and DMSO-water mixtures.
authors: Department of Chemistry and Chemical Biology, BioMaPS Institute for Quantitative Biology, Rutgers University, 610 Taylor Rd., Piscataway, NJ 08854, USA.
authors: Junchao
authors: J
authors: Xia
authors: David A
authors: DA
authors: Case
mesh_terms: D004121:Dimethyl Sulfoxide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D056004:Molecular Dynamics Simulation; D012996:Solutions; D013395:Sucrose / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D013395:Sucrose; D004121:Dimethyl Sulfoxide