title: Efficient chi-tensor determination and NH assignment of paramagnetic proteins.
abstract: Anisotropic magnetic susceptibility tensors chi 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 chi-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 chi-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 epsilon from E. coli DNA polymerase III in complex with the subunit theta and La3+ in its diamagnetic and Dy3+, Tb3+, and Er3+ in its paramagnetic form.
authors.affiliation: Department of Mathematics, University of Queensland, Brisbane, QLD, 4072, Australia.
authors.forename: Christophe
authors.initials: C
authors.lastname: Schmitz
authors.forename: Michael
authors.initials: M
authors.lastname: John
authors.forename: Ah Young
authors.initials: AY
authors.lastname: Park
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Dixon
authors.forename: Gottfried
authors.initials: G
authors.lastname: Otting
authors.forename: Guido
authors.initials: G
authors.lastname: Pintacuda
authors.forename: Thomas
authors.initials: T
authors.lastname: Huber
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D004258:DNA Polymerase III / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology; D028581:Lanthanoid Series Elements / Q000737:chemistry; D008280:Magnetics; D008667:Metalloproteins / Q000737:chemistry*; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D021122:Protein Subunits / Q000737:chemistry; D012984:Software
chemical_list: D028581:Lanthanoid Series Elements; D008667:Metalloproteins; D009587:Nitrogen Isotopes; D021122:Protein Subunits; D004258:DNA Polymerase III