title: Asymmetry in 13C-13C COSY spectra provides information on ligand geometry in paramagnetic proteins.
abstract: The relative intensity of Calpha-C' cross-peaks in homonuclear 13C COSY spectra depends on the relaxation properties of Calpha and C' spins, which, in the proximity of a paramagnetic center, are related to the metal-to-carbon distance. Their quantitative analysis has lead, for the cerium-substituted dicalcium protein, calbindin D9k, to the straightforward identification of peaks arising from metal-coordinating groups. The monodentate or bidentate metal binding mode of carboxylates was identified directly via NMR.
authors.affiliation: Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy. ivanobertini@cerm.unifi.it
authors.forename: Ivano
authors.initials: I
authors.lastname: Bertini
authors.forename: Beatriz
authors.initials: B
authors.lastname: Jiménez
authors.forename: Mario
authors.initials: M
authors.lastname: Piccioli
authors.forename: Luisa
authors.initials: L
authors.lastname: Poggi
mesh_terms: D000465:Algorithms; D002247:Carbon Isotopes / Q000737:chemistry; D008024:Ligands; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D008024:Ligands; D011506:Proteins