title: Cross-relaxation bottleneck in water-lysozyme proton magnetization exchange.
abstract: The proton spin-lattice relaxation parameters in natural and deuterated lysozyme solutions have been measured as a function of temperature (0-50 degrees C). The variation of the apparent magnitudes of the water proton magnetizations in the solutions with temperature indicates that magnetic coupling mixes protein and water proton magnetizations. The results are consistent with an exchange cross-relaxation model (Hills, B. P., Mol Phys 1992, 76, 489-508) in which the cross-relaxation acts between the labile and nonlabile protons, rather than between water and protein protons. Although this cross-relaxation pathway clearly affects the observed magnetization fractions in this protein solution, its influence on the relaxation rates is less apparent.
authors.affiliation: Department of Physics, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3.
authors.forename: J F
authors.initials: JF
authors.lastname: Kakule
authors.forename: A R
authors.initials: AR
authors.lastname: Sharp
authors.forename: L J
authors.initials: LJ
authors.lastname: Schreiner
authors.forename: R T
authors.initials: RT
authors.lastname: Thompson
authors.forename: T
authors.initials: T
authors.lastname: Kupka
authors.forename: R
authors.initials: R
authors.lastname: Holly
authors.forename: H
authors.initials: H
authors.lastname: Peemoeller
mesh_terms: D000818:Animals; D001704:Biopolymers / Q000737:chemistry; D003903:Deuterium; D066298:In Vitro Techniques; D008280:Magnetics; D009113:Muramidase / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011522:Protons; D014867:Water
chemical_list: D001704:Biopolymers; D011522:Protons; D014867:Water; D003903:Deuterium; D009113:Muramidase