The 2D [31P] spin-echo-difference constant-time [13C, 1H]-HMQC experiment for simultaneous determination of 3J(H3'P) and 3J(C4'P) in 13C-labeled nucleic acids and their protein complexes

J Magn Reson. 1999 Oct;140(2):491-4. doi: 10.1006/jmre.1999.1870.

Abstract

A two-dimensional [31P] spin-echo-difference constant-time [13C, 1H]-HMQC experiment (2D [31P]-sedct-[13C, 1H]-HMQC) is introduced for measurements of 3J(C4'P) and 3J(H3'P) scalar couplings in large 13C-labeled nucleic acids and in DNA-protein complexes. This experiment makes use of the fact that 1H-13C multiple-quantum coherences in macromolecules relax more slowly than the corresponding 13C single-quantum coherences. 3J(C4'P) and 3J(H3'P) are related via Karplus-type functions with the phosphodiester torsion angles beta and epsilon, respectively, and their experimental assessment therefore contributes to further improved quality of NMR solution structures. Data are presented for a uniformly 13C, 15N-labeled 14-base-pair DNA duplex, both free in solution and in a 17-kDa protein-DNA complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon / chemistry
  • Carbon Isotopes
  • DNA / chemistry
  • Humans
  • Hydrogen / chemistry
  • Hydrogen Bonding
  • Macromolecular Substances
  • Magnetic Resonance Spectroscopy* / methods
  • Nucleic Acids / chemistry*
  • Nucleotides / chemistry
  • Phosphorus Isotopes
  • Proteins / chemistry*
  • Time Factors

Substances

  • Carbon Isotopes
  • Macromolecular Substances
  • Nucleic Acids
  • Nucleotides
  • Phosphorus Isotopes
  • Proteins
  • Carbon
  • Hydrogen
  • DNA