Tutorial for Relaxation dispersion analysis cpmg fixed time recorded on varian as fid interleaved

Intro

This tutorial is based on the analysis of NMR data from the paper:

The inverted chevron plot measured by NMR relaxation reveals a native-like unfolding intermediate in acyl-CoA binding protein.
Kaare Teilum, Flemming M Poulsen, Mikael Akke.
Proceedings of the National Academy of Sciences of the United States of America (2006).
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1458987

The data is recorded as FID interleaved

Preparation

You want to make a working dir, with different folders

peak_lists
spectrometer_data
scripts

You can create the folders by

mkdir peak_lists spectrometer_data scripts

In the folder spectrometer_data should be the files: fid and procpar as the output from recording fid interleaved on Varian.
In the folder peak_lists should contain SPARKY list in SPARKY list format.
In the folder scripts we put scripts which help us processing the files.

Get the process helper scripts

cd scripts
# Change shell
tcsh
# Set array of scripts to download
set SCRIPTS="CPMG_1_sort_pseudo3D_initialize_files.sh CPMG_2_convert_and_process.sh CPMG_3_fft_all.sh convert_all.com fft_all.com sparky_add.sh stPeakList.pl NMRPipe_to_Sparky.sh"

# Download scripts
foreach SCRIPT ( ${SCRIPTS} )
curl https://raw.github.com/nmr-relax/relax_scripts/master/shell_scripts/$SCRIPT -o $SCRIPT
end

# Make them executable
chmod +x *.sh *.com *.pl

# Go back to previous directory
cd ..

Extract interleaved spectra, process to NMRPipe and do spectral processing

Extract interleaved and change format to NMRPipe

sort out the interleaved fid with the script CPMG_1_sort_pseudo3D_initialize_files.sh.

# Copy data
cp -r spectrometer_data spectrometer_data_processed

# sort_pseudo3D and initialize files
cd spectrometer_data_processed
CPMG_1_sort_pseudo3D_initialize_files.sh

Now we make a file to convert from binary format of Varian to NMRPipe.

1. Now click, 'read parameters', check 'Rance-Kay'
2. Remember to set Y-'Observe Freq MHz' to N15
3. Click 'Save script' to make 'fid.com' file, and 'Quit', and run the next CPMG script

Now it is time to convert all the fid from varian format to NMRPipe with the script CPMG_2_convert_and_process.sh.

CPMG_2_convert_and_process.sh

Spectral processing

1. Now we need to spectral process the spectra.
2. Process one of the files normally and the next script will copy the processing script to the other folder.
3. [m]->Right-Click Process 2D->Basic 2D
4. Save->Execute->Done; then; RClick File->Select File->test.ft2->Read/draw->Done
5. If your spectra look reversed (i.e. if your peaks do not seem to match your reference spectrum) it might be solved by changing to
6. [m] '| nmrPipe -fn FT -neg \' to the script to the third lowest line.
7. Save->Execute->Done. Then push [r] to refresh.
8. Press [h], and find P0 and P1, and push [m], change parameters and update script
9. The changes to '| nmrPipe -fn PS xxx \' should be the FIRST line (The proton dimension) with PS
10. save/execute, push [r] (read) and the [e] (erase settings) to see result in NMRdraw
11. And then run the next CPMG script

As suggested in the relax manaul, section 5.2.2 Spectral processing, the spectral processing script could look like: File: nmrproc.com

#!/bin/csh

nmrPipe -in test.fid \
| nmrPipe  -fn SOL                                    \
| nmrPipe  -fn GM  -g1 5 -g2 10 -c 0.5                \
| nmrPipe  -fn ZF -auto -size 8000                    \
| nmrPipe  -fn FT -auto                               \
| nmrPipe  -fn PS -p0 214.00 -p1 -21.00 -di -verb     \
| nmrPipe  -fn TP                                     \
| nmrPipe  -fn SP -off 0.5 -end 0.98 -pow 2 -c 0.5    \
| nmrPipe  -fn ZF -auto -size 8000                    \
| nmrPipe  -fn FT -neg                                \
| nmrPipe  -fn PS -p0 0.00 -p1 0.00 -di -verb         \
| nmrPipe  -fn TP                                     \
| nmrPipe  -fn POLY -auto                             \
| nmrPipe  -fn EXT -left -sw                          \
   -ov -out test.ft2

Fourier transform all spectra

Now it is time to Fourier Transform all spectra with the script CPMG_3_fft_all.sh.

CPMG_3_fft_all.sh

Convert all *.ft2 files to ucsf format, so they can be opened in SPARKY

Done by the script NMRPipe_to_Sparky.sh

NMRPipe_to_Sparky.sh

Check the peak list matches

sparky 0.fid/test.ucsf

SPARKY GUI

The keyboard shortcuts are listed in the manual [1]

First make window bigger.
zo for zoom out. zi Zoom in.

ct for setting countour level.
Set level 6 for positive and negative.
Add 1 to the +e0x level. Ex: xxxe+03 -> xxxe+04 ind positive and negative.
Ok

rp for read peaks. Find your peak file.

../peak_lists/peaks.list

Click Create peaks, Close.

Shift all peaks

Select on peak, and center it.
lt (LT) to show a list of peaks for a spectrum.
Double click on peak "A3N" in the list. Zoom in "zi".

Now you want to align you peaks, since they can be off-shifted.
First note down the current value of PPM in w1 and w2.

A3N-HN	121.828	8.513

Push F1 for select mode, drag it with the mouse or "pc" for auto "peak center".
Then click "Update" in the peak list, and note down the new values.

A3N-HN	121.681	8.514

We need to shift the nitrogen peaks 
(121.681 - 121.828)=-0.147 ppm, 
and proton peaks 
(8.514 - 8.513)=0.001 ppm.

Exit SPARKY

Go to the peak_list folder.

cd ../peak_lists/

Correct Nitrogen

sparky_add.sh peaks.list '$2' -0.147 peaks_corr_N15.list

Correct Proton

sparky_add.sh peaks_corr_N15.list '$3' 0.001 peaks_corr_N15_1H.list

Check and auto center peaks

Now go into Sparky again, and read peak list.

cd ..
cd spectrometer_data_processed
sparky 0.fid/test.ucsf

rp Choose ../peak_lists/peaks_corr_N15_1H.list
Create peaks, close.
zo zoom out. ct set contour.
lt and go through peaks, and auto center with pc.

Problematic peaks:

H30N-HN, not possible to auto center in the middle. Next to L47 and E4.
A57N-HN / D68N-HN  In original peak list: A57N-HN 121.526 7.944 / D68N-HN 121.511 7.922, both centered to: 121.409 7.933.

Manually alter peaks

Save file to: ../peak_lists/peaks_corr_peak_center.list and then alter values manual.

cp ../peak_lists/peaks_corr_peak_center.list ../peak_lists/peaks_corr_final.list 
gedit ../peak_lists/peaks_corr_final.list &

Then alter to:

H30N-HN 117.794 8.045
A57N-HN	121.417 7.944
D68N-HN	121.402 7.922

Then check again in sparky.

Check for peak movement

As stated in the | relax manual section 5.2.1 Temperature control and calibration, the pulse sequence can put a lot of power into the sample.

It is therefore good practice to inspect for peak movements, by overlaying all spectra:

Open all the files, and overlay them with SPARKY command ol.

sparky 0.fid/test.ucsf 1.fid/test.ucsf 2.fid/test.ucsf 3.fid/test.ucsf 4.fid/test.ucsf

Changes colours for different spectra in contour ct.
Then overlay with "ol". Make sure no peaks move around.