Note:
The magnetization is passed from ${\phantom{A}}_{\phantom{}}^{\phantom{1}}{\phantom{A}}_{\phantom{2}}^{\phantom{2}1}\mathrm{H}$ to ${\phantom{A}}_{\phantom{}}^{\phantom{15}}{\phantom{A}}_{\phantom{2}}^{\phantom{2}15}\mathrm{N}$ and then via the $\mathrm{N}-\mathrm{C}\mathrm{\alpha }$ $\mathrm{J}\text{-}\mathrm{c}\mathrm{o}\mathrm{u}\mathrm{p}\mathrm{l}\mathrm{i}\mathrm{n}\mathrm{g}$ to the ${\phantom{A}}_{\phantom{}}^{\phantom{13}}{\phantom{A}}_{\phantom{2}}^{\phantom{2}13}\mathrm{C}\mathrm{\alpha }$ and then back again to ${\phantom{A}}_{\phantom{}}^{\phantom{15}}{\phantom{A}}_{\phantom{2}}^{\phantom{2}15}\mathrm{N}$ and ${\phantom{A}}_{\phantom{}}^{\phantom{1}}{\phantom{A}}_{\phantom{2}}^{\phantom{2}1}\mathrm{H}$ hydrogen for detection. Each $\mathrm{NH}$ group will show correlations to both their own and the previous residue’s ${\phantom{A}}_{\phantom{}}^{\phantom{13}}{\phantom{A}}_{\phantom{2}}^{\phantom{2}13}\mathrm{C}\mathrm{\alpha }$.