title: Hexagonal ice in pure water and biological NMR samples.
abstract: Ice, in addition to "liquid" water and protein, is an important component of protein samples for NMR spectroscopy at subfreezing temperatures but it has rarely been observed spectroscopically in this context. We characterize its spectroscopic behavior in the temperature range from 100 to 273 K, and find that it behaves like pure water ice. The interference of magic-angle spinning (MAS) as well as rf multiple-pulse sequences with Bjerrum-defect motion greatly influences the ice spectra.
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bauer
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Gath
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hunkeler
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland. maer@ethz.ch.
authors.forename: Matthias
authors.initials: M
authors.lastname: Ernst
authors.affiliation: Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS, Université de Lyon 1, 7 passage du Vercors, 69367, Lyon, France. a.bockmann@ibcp.fr.
authors.forename: Anja
authors.initials: A
authors.lastname: Böckmann
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland. beme@ethz.ch.
authors.forename: Beat H
authors.identifier: 0000-0002-9107-4464
authors.initials: BH
authors.lastname: Meier
mesh_terms: D000465:Algorithms; D007053:Ice / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D014867:Water / Q000737:chemistry*
chemical_list: D007053:Ice; D014867:Water
keywords: Dynamics; Fibrils; Ice: protein; MAS; NMR; Polarization-transfer; Water