Table 1.

Definitions of the chemical shift perturbation categories in Figure 3.

Chemical Shift Perturbation	Definition	vCCI Chemical Shift	vMIP-II Chemical Shift
0	No confirmable change	No peaks visible	No peaks visible
1	Less than or equal to average	Δδobs ≤ 0.045	Δδobs ≤ 0.100
2	Greater than average, up to one standard deviation above average	0.045 < Δδobs ≤ 0.086	0.100 < Δδobs ≤ 0.178
3	Greater than one standard deviation above average	Δδobs ≥ 0.086	Δδobs ≥ 0.178

Δδobs: the difference in chemical shift between bound and free form of ¹⁵N-labeled complexes, as defined in Methods.