Fig. 4.

2D non-constant time HSQC spectra of all four labeled nucleotides showing the increased level of labeling in K10 with formate in a 2-glycerol background without introducing significant multiplet splitting in the ribose ring carbons atoms which contrasts with the uniformly labeled nucleotides. The spectra of uniformly labeled nucleotides are shown to the right of the site specific labeled rNMPs. For the uniformly labeled nucleotide AMP = blue, GMP = red, CMP = blue and UMP = purple. Note how the uniformly labeled rNMPs suffer from multiplet splitting absent in the new labels. a Ribose C4′, b Ribose C2′, c Ribose C1′ and d Ribose C5′. The resonances from each of the four nucleotides are annotated for adenine (Ade), cytosine (Cyt), guanine (Gua), and uracil (Ura). Not shown is C3′ that has doublet splitting instead of triplet seen in the uniformly labeled NMP sample