Asymmetry in 13C-13C COSY spectra provides information on ligand geometry in paramagnetic proteins.
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.
Bertini
Ivano
I
Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy. ivanobertini@cerm.unifi.it
Jiménez
Beatriz
B
Piccioli
Mario
M
Poggi
Luisa
L
D000465:Algorithms; D002247:Carbon Isotopes / Q000737:chemistry; D008024:Ligands; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*
D002247:Carbon Isotopes; D008024:Ligands; D011506:Proteins