NMR assignment of polynucleotides
From NMR Wiki
Assignment of nucleobase resonances
Conventional method uses NOE-based correlations: imino protons → non-exchangeable aromatic protons → H1' ribose/deoxy-ribose[1].
Adenine and cytosine don't have imino groups. For these, assignment of nucleobases can be done starting with the across the base-pair NOEs. Article[1] discusses several experiments for the assignment of nucleobases, including HNN-COSY,2J-15N-HSQC, TROSY-relayed HCCH-COSY, 13C-HMBC and proposed an experiment called 3D-(15N,13C,1H)-HNHC.
The latter experiment is a combination of 13C-HSQC and 2J-15N-HSQC. Article [1] also contains a scheme of some J couplings in the adenine base.
