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The step above makes the crossrelaxation rates σi,j in correct mutual proportion. The actual values can be still inaccurate due to inaccurate reference distance, rRef in Eq. 1, or rather σRef being not correctly proportional to the rRef due to spin diffusion or other effects. It is therefore recommendable to correct the median of the measured distances such that it corresponds to the distances conserved among these organic molecules: around 4.2 Å for intramolecular distances and 4.4 Å for the intermolecular distances. When correcting the derived distances, we include a constant to multiply the distances in order to obtain the desired median.
c:
There is an important technical detail about how the CYANA handles the sites with multiple spins - such as -CH3, with three spins with the same chemical shift. These three spins combined into a pseudoatom Q, but, the distance between this atom another atom is not the average but instead a shorter distance, calculated from the three-fold intensity of the NOE crosspeak. Similarly for crosspeak between two methyl groups, the crosspeak would be 9x larger than expected from one atom, and it will be translated to a very short distance expected by CYANA.
Task 2: Redo the normalization
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