USE OF DIPOLAR H-1-N-15 AND H-1-C-13 COUPLINGS IN THE STRUCTURE DETERMINATION OF MAGNETICALLY ORIENTED MACROMOLECULES IN SOLUTION

Anisotropy of the molecular magnetic susceptibility gives rise to a sm all degree of alignment, The resulting residual dipolar couplings, whi ch can now be measured with the advent of higher magnetic fields in NM R, contain information on the orientation of the internuclear vectors relative to the molecular magnetic susceptibility tensor, thereby prov iding information on long range order that is not accessible by any of the solution NMR parameters currently used in structure determination . Thus, the dipolar couplings constitute unique and powerful restraint s in determining the structures of magnetically oriented macromolecule s in solution, The method is demonstrated on a complex of the DNA-bind ing domain of the transcription factor GATA-1 with a 16 base pair olig odeoxyribonucleotide.