Medium and Long-Range NOE Correlations

So far we have not learned anything from the NOE data except to assign all of the protons. This is an essential first step, but the real goal is to extract distances between specific pairs of protons from the NOE data. Sequential NOEs are not very useful because we already know that an amino acid residue is close in space to its nearest neighbor in the sequence. The real mother lode of the NOESY data consists of the medium-range (i - i + 2, i — i + 3 and i - i + 4) and long-range connectivities. These define the secondary structure 

Deuterium exchange is measured by recording a series of fast TOCSY experiments (30 min each) immediately after dissolving the protein in D2O. As the amide protons 

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