Experimental and theoretical determination of nucleic acid magnetic susceptibility: importance for the study of dynamics by field-induced residual dipolar couplings

J Am Chem Soc. 2004 Sep 8;126(35):10820-1. doi: 10.1021/ja047179o.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anisotropy
  • DNA / chemistry*
  • DNA-Binding Proteins / chemistry
  • Erythroid-Specific DNA-Binding Factors
  • Magnetics*
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Nucleic Acids / chemistry*
  • Transcription Factors / chemistry

Substances

  • DNA-Binding Proteins
  • Erythroid-Specific DNA-Binding Factors
  • Nucleic Acids
  • Transcription Factors
  • DNA