Efficient χ-tensor determination and NH assignment of paramagnetic proteins

Authors

Christophe Schmitz, University of Queensland
Michael John, Australian National University
Ah-Young Park, Australian National University
Nicholas E. Dixon, University of WollongongFollow
Gottfried Otting, Australian National University
Guido Pintacuda, Ecole Normale Sup Rieure de Lyon
Thomas Huber, University Of Queensland

RIS ID

16840

Publication Details

Schmitz, C., John, M., Park, A., Dixon, N. E., Otting, G., Pintacuda, G. & Huber, T. (2006). Efficient chi-tensor determination and HN assignment of paramagnetic proteins. Journal of Biomolecular N M R, 35 (2), 79-87.

Abstract

Anisotropic magnetic susceptibility tensors χ of paramagnetic metal ions are manifested in pseudocontact shifts, residual dipolar couplings, and other paramagnetic observables that present valuable long-range information for structure determinations of protein-ligand complexes. A program was developed for automatic determination of the χ-tensor anisotropy parameters and amide resonance assignments in proteins labeled with paramagnetic metal ions. The program requires knowledge of the three-dimensional structure of the protein, the backbone resonance assignments of the diamagnetic protein, and a pair of 2D ¹⁵N-HSQC or 3D HNCO spectra recorded with and without paramagnetic metal ion. It allows the determination of reliable χ-tensor anisotropy parameters from 2D spectra of uniformly ¹⁵N-labeled proteins of fairly high molecular weight. Examples are shown for the 185-residue N-terminal domain of the subunit ε from E. coli DNA polymerase III in complex with the subunit θ and La³⁺ in its diamagnetic and Dy³⁺, Tb³⁺, and Er³⁺ in its paramagnetic form.