title: Structure-independent cross-validation between residual dipolar couplings originating from internal and external orienting media.
abstract: Lanthanide-substituted calcium binding proteins are known to partially orient in high magnetic fields. Orientation provides residual dipolar couplings (rdc's). Two of these systems, Tm3+- and Dy3+-substituted calbindin D9k, dissolved in an external orienting medium (nonionic liquid crystalline phase) provide rdc values which are the sum of those induced by the lanthanides and by the liquid crystalline phase on the native calcium binding protein. This structure-independent check shows the innocence of the orienting medium with respect to the structure of the protein in solution. Furthermore, the simultaneous use of lanthanide substitution and external orienting media provides a further effective tool to control and tune the orientation tensor.
authors.affiliation: Magnetic Resonance Center CERM, Department of Chemistry, University of Florence, Sesto Fiorentino, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Barbieri
authors.forename: Ivano
authors.initials: I
authors.lastname: Bertini
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Lee
authors.forename: Claudio
authors.initials: C
authors.lastname: Luchinat
authors.forename: Aldrik H
authors.initials: AH
authors.lastname: Velders
mesh_terms: D064026:Calbindins; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D015203:Reproducibility of Results; D064030:S100 Calcium Binding Protein G / Q000737:chemistry*; D013223:Statistics as Topic
chemical_list: D064026:Calbindins; D028581:Lanthanoid Series Elements; D064030:S100 Calcium Binding Protein G