FIGURE 5.

Real-time phosphorylation of ¹⁵N-labeled HMG-D monitored by ¹⁵N HSQC NMR spectroscopy. a, spectra are colored black through to red to indicate the increasing time. Peaks arising from Ser¹⁰³ and Ser¹¹¹ undergo a significant chemical shift change shown by the arrow, indicative of phosphorylation. The intensity of the original peak falls with time, whereas the intensity of the corresponding peak in the new position grows. b, quantification of the intensity of the new peaks seen in a. arb. units, arbitrary units.