Take a theoretical protein of 200 residues for example: there should be 240 N-H HSQC correlations (considering ASN, GLN, and et al) on NMR spectrum.
However, due to the efficiency/efficacy of 15N labelling, not all nitrogen atoms in the protein are labelled.
So is it possible for the protein harvested from growth medium A to have 180 peaks on 1H-15N HSQC spectrum while that from growth medium B to have a different set of 180 peaks, and only 150 of these peaks are shared (overlapped) between A and B?
Thanks,
Yun