Experimental and theoretical determination of nucleic acid magnetic susceptibility: importance for the study of dynamics by field-induced residual dipolar couplings.
Magnetic susceptibility anisotropies (Deltachi) are determined for the nucleic acid bases on the basis of a combined NMR spectroscopic and DFT study. Magnetic field-induced residual dipolar couplings (RDC) measured for the Dickerson dodecamer allow for the determination of a precise value of Deltachi for this DNA. A tensor summation employing the results of DFT calculations of the individual base magnetic susceptibility tensors and the known structure of the dodecamer provides a value of Deltachi which is in excellent agreement with experiment. The DFT results are shown to provide superior agreement with experiment for the dodecamer and a protein-DNA complex when compared with other sets of values in common use in the literature. The marked discrepancy between our Deltachi values and existing sets of values has a direct and significant impact on the interpretation of field-induced anisotropic interactions in terms of biomolecular structure and dynamics.
Bryce
David L
DL
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
Boisbouvier
Jérôme
J
Bax
Ad
A
D016880:Anisotropy; D004247:DNA / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry; D050981:Erythroid-Specific DNA-Binding Factors; D008280:Magnetics; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D009696:Nucleic Acids / Q000737:chemistry*; D014157:Transcription Factors / Q000737:chemistry
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D009696:Nucleic Acids; D014157:Transcription Factors; D004247:DNA