Estimates of methyl 13C and 1H CSA values (Deltasigma) in proteins from cross-correlated spin relaxation

J Biomol NMR. 2004 Dec;30(4):397-406. doi: 10.1007/s10858-004-4349-x.

Abstract

Simple pulse schemes are presented for the measurement of methyl (13)C and (1)H CSA values from (1)H-(13)C dipole/(13)C CSA and (1)H-(13)C dipole/(1)H CSA cross-correlated relaxation. The methodology is applied to protein L and malate synthase G. Average (13)C CSA values are considerably smaller for Ile than Leu/Val (17 vs 25 ppm) and are in good agreement with previous solid state NMR studies of powders of amino acids and dipeptides and in reasonable agreement with quantum-chemical DFT calculations of methyl carbon CSA values in peptide fragments. Small averaged (1)H CSA values on the order of 1 ppm are measured, consistent with a solid state NMR determination of the methyl group (1)H CSA in dimethylmalonic acid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Carbon Isotopes
  • DNA-Binding Proteins / chemistry
  • Malate Synthase / chemistry
  • Methylation
  • Nuclear Magnetic Resonance, Biomolecular*
  • Peptostreptococcus / chemistry
  • Protons

Substances

  • Bacterial Proteins
  • Carbon Isotopes
  • DNA-Binding Proteins
  • L-protein, Peptococcus magnus
  • Protons
  • Malate Synthase