title: Measurement of long-range 1H-1H dipolar couplings in weakly aligned proteins.
abstract: Measurement of 1H-1H dipolar couplings in macromolecules, weakly oriented by a dilute liquid crystalline medium, is generally limited to the largest such interactions. By removing dipolar couplings to nearest neighbors, either by decoupling, deuteration, or both, more remote interactions become accessible. The approach is demonstrated for measurement of amide-amide interactions in the proteins calmodulin and ubiquitin and permits observation of direct dipolar couplings between protons up to 7 A apart. Quantitative evaluation of 1H-1H dipolar couplings measured in ubiquitin shows excellent agreement with its solution structure.
authors.affiliation: Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Wu
authors.forename: Ad
authors.initials: A
authors.lastname: Bax
mesh_terms: D002147:Calmodulin / Q000737:chemistry*; D008280:Magnetics; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D025801:Ubiquitin / Q000737:chemistry*
chemical_list: D002147:Calmodulin; D025801:Ubiquitin