title: Structure and dynamics of an RNA tetraloop: a joint molecular dynamics and NMR study.
abstract: Molecular dynamics simulations of the RNA tetraloop 5'-CGCUUUUGCG-3' with high melting temperature and significant conformational heterogeneity in explicit water solvent are presented and compared to NMR studies. The NMR data allow for a detailed test of the theoretical model, including the quality of the force field and the conformational sampling. Due to the conformational heterogeneity of the tetraloop, high temperature (350 K) and locally enhanced sampling simulations need to be invoked. The Amber98 force field leads to a good overall agreement with experimental data. Based on NMR data and a principal component analysis of the 350 K trajectory, the dynamic structure of the tetraloop is revealed. The principal component free energy surface exhibits four minima, which correspond to well-defined conformational structures that differ mainly by their base stacking in the loop region. No correlation between the motion of the sugar rings and the stacking dynamics of the loop bases is found.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance, Johann Wolfgang Goethe-University, Frankfurt, Marie-Curie-Str 11, D-60439 Frankfurt/Main, Germany.
authors.forename: Jessica
authors.initials: J
authors.lastname: Koplin
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Mu
authors.forename: Christian
authors.initials: C
authors.lastname: Richter
authors.forename: Harald
authors.initials: H
authors.lastname: Schwalbe
authors.forename: Gerhard
authors.initials: G
authors.lastname: Stock
mesh_terms: D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D012313:RNA