2D IPAP [13C-1H3] CT-HSQC

Georg Kontaxis and Ad Bax
Feb 26, 2001

CITATION

Multiplet Component Separation for Measurement of Methyl 13C-1H
Dipolar Couplings in Weakly Aligned Proteins
J. Biomol. NMR 2001, submitted

CONTACT

Georg Kontaxis
kontaxis@speck.niddk.nih.gov

SUMMARY

This experiment measures 13C-1H dipolar couplings in methyl groups
by separating the four lines of a methyl quartet into different subspectra.
It acquires four interleaved 1H coupled CT-HSQC spectra with an editing delay 
for evolution of JCH, which is set to 0.0, 1.33, 2.66, 4.0 ms in turn.

To process the data the fid file has to be separated into four different files
which are processed separately and linear combined to yield the desired
subspectra.

The typical processing and analysis steps are as follows:

1. fid.com

   The ser file from the spectrometer is converted to NMRPipe format
   (can be generated automatically by graphical spectrometer format 
   conversion tool)

2. split.com

   The interleaved fid file is split into 4 different datasets (A-D).

3. ft2.com

   Each of the spectra is Fourier transformed using standard States processing.

4. lc.com

   The resulting files are combined to extract particular multiplet
   components.  The coefficients for the co-additions may need adjustment 
   to account for transverse relaxation:

   A+2B+2C+D.ft2   # Most downfield line.
   A-B-C+D.ft2     # Center upfield line.
   A+B-C-D.ft2     # Center downfield line.
   A-2B+2C-D.ft2   # Most upfield line.