Friday, April 23, 2004
Nuclear Overhauser Effect (NOE) Links to Neighboring Residues
The chemical shift values for the unphosphorylated tissue factor cytoplasmic tail provides good insight and confirmation of the amino acid sequence. The major classification of the spin systems was completed using the TOC peaks and collaborated by inphase homonuclear 2D correlated spectroscopy (IP_COSY) experimental data. The TOC peaks have random coil H chemical shifts that loosely match consistent patterns that are published (NMR of Proteins and Nucleic Acids: Kurt Wuthrich). Then the NOE data is evaluated for resonance peaks between the n and n+1 residues. The graph shows the NOE data set for the main backbone assignment of this polypeptide. As you can see the peak number fifteen (#15) in the upper left is a link between the residues corresponding to peaks eight (#8) and eighteen (#18) For this peptide, peak eight is Tryptophan-254 and peak eighteen is Lysine-255. Likewise you can go through the rest of the NOE peak list and develop sequential data. The graph also demonstrates the difficulty in automation of this process. Peaks, six(#6), eleven(#11), and twenty-one(#21) are actually multiple peaks confounded in the overlap of their chemical shifts. In addition a number of peaks are "bleached out" by the solvent at the N-terminus end.
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The chemical shift values for the unphosphorylated tissue factor cytoplasmic tail provides good insight and confirmation of the amino acid sequence. The major classification of the spin systems was completed using the TOC peaks and collaborated by inphase homonuclear 2D correlated spectroscopy (IP_COSY) experimental data. The TOC peaks have random coil H chemical shifts that loosely match consistent patterns that are published (NMR of Proteins and Nucleic Acids: Kurt Wuthrich). Then the NOE data is evaluated for resonance peaks between the n and n+1 residues. The graph shows the NOE data set for the main backbone assignment of this polypeptide. As you can see the peak number fifteen (#15) in the upper left is a link between the residues corresponding to peaks eight (#8) and eighteen (#18) For this peptide, peak eight is Tryptophan-254 and peak eighteen is Lysine-255. Likewise you can go through the rest of the NOE peak list and develop sequential data. The graph also demonstrates the difficulty in automation of this process. Peaks, six(#6), eleven(#11), and twenty-one(#21) are actually multiple peaks confounded in the overlap of their chemical shifts. In addition a number of peaks are "bleached out" by the solvent at the N-terminus end.
