title: Effect of temperature on the low-frequency vibrational spectrum and relative structuring of hydration water around a single-stranded DNA.
abstract: Molecular dynamics simulations of the single-stranded DNA oligomer (5'-CGCGAAT TCGCG-3') in aqueous solution have been carried out at different temperatures between 160 K and 300 K. The effects of temperature on the low-frequency vibrational spectrum and local structural arrangements of water molecules hydrating the DNA strand have been explored in detail. The low-frequency density of states distributions reveal that increasingly trapped transverse water motions play a dominant role in controlling the band corresponding to O⋯O⋯O bending or transverse oscillations of hydration water at supercooled temperatures. In addition, presence of a broad band around 260 (±20) cm(-1) under supercooled conditions indicates transformation from high density liquid-like structuring of hydration water at higher temperatures to that of a low density liquid at lower temperatures. It is found that long-range correlations between the supercooled hydration water molecules arise due to such local structural transition around the DNA oligomer.
authors.affiliation: Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Chakraborty
authors.affiliation: Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
authors.forename: Sanjoy
authors.initials: S
authors.lastname: Bandyopadhyay
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D013057:Spectrum Analysis; D013696:Temperature; D014732:Vibration; D014867:Water / Q000737:chemistry*
chemical_list: D004277:DNA, Single-Stranded; D014867:Water