TABLE 3.

Fitting parameters format and examples for each fit type.

Fit type	Parameter list (in prescribed order) and description	Example param[X].txt entries (initial value, lower bound, upper bound, fix parameter)
0	Fraction of the exchanging species in NMR-visible state	0.95, 0.01, 1.0, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	k3 (s−1), rate constant from tethered to direct-contact state	0.1, 1e-6, 1e6, 0
	$R_2^{\text{contact}}({\text{s}}^{-1})$, R2 in direct-contact dark state	19e3, 500, 1e7, 0
	$R_2^{\text{tethered}}({\text{s}}^{-1})$, residue-specific R2 in tethered state	200, 20, 1e7, 0
	K3, residue-specific equilibrium constant equal to [direct-contact] / [tethered]	1, 1e-9, 1e9, 0
1	Fraction of the exchanging species in NMR-visible state	0.95, 0.01, 1.0, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	$R_2^{\text{contact}}({\text{s}}^{-1})$, R2 in direct-contact dark state	19e3, 500, 1e7, 0
	$R_2^{\text{tethered}}({\text{s}}^{-1})$, residue-specific R2 in tethered state	200, 20, 1e7, 0
	K3, residue-specific equilibrium constant equal to [direct-contact] / [tethered]	1, 1e-9, 1e9, 0
2	Fraction of the exchanging species in NMR-visible state	0.95, 0.01, 1.0, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, on-rate to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	$k_{\text{2}}^{\text{dark}}({\text{s}}^{-1})$, residue-specific R2 in dark state	200, 20, 1e7, 0
3	Fraction of the exchanging species in NMR-visible state	0.90, 0.01, 0.99, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	Fraction of the exchanging species in dark state 1	0.1, 0.01, 0.3, 0
	k3 (s−1), rate constant from dark state 1 to dark state 2	0.1, 1e-6, 1e6, 0
	k−1 (s−1), rate constant from dark state 1 to visible state (‘off-rate’)	0.1, 1e-6, 1e6, 0
	$R_2^{\text{dark}(1)}({\text{s}}^{-1})$, residue-specific R2 in dark state 1	200, 20, 1000, 0
	$R_2^{\text{dark}(2)}({\text{s}}^{-1})$, residue-specific R2 in dark state 2	5000, 1000, 1e9, 0
4	Fraction of the exchanging species in NMR-visible state	0.90, 0.01, 0.99, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	Fraction of the exchanging species in dark state 1	0.1, 0.01, 0.3, 0
	k3 (s−1), rate constant from dark state 1 to dark state 2	0.1, 1e-6, 1e6, 0
	$R_2^{\text{dark}(1)}({\text{s}}^{-1})$, residue-specific R2 in dark state 1	200, 20, 1000, 0
	$R_2^{\text{dark}(2)}({\text{s}}^{-1})$, residue-specific R2 in dark state 2	5000, 1000, 1e9, 0
5	Fraction of the exchanging species in NMR-visible state	0.90, 0.01, 0.99, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	Fraction of the exchanging species in dark state 1	0.1, 0.01, 0.3, 0
	k−1 (s−1), rate constant from dark state 1 to visible state (‘off-rate’)	0.1, 1e-6, 1e6, 0
	$R_2^{\text{dark}(1)}({\text{s}}^{-1})$, residue-specific R2 in dark state 1	200, 20, 1000, 0
	$R_2^{\text{dark}(2)}({\text{s}}^{-1})$, residue-specific R2 in dark state 2	5000, 1000, 1e9, 0
6	Fraction of the exchanging species in NMR-visible state	0.90, 0.01, 0.99, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	Fraction of the exchanging species in dark state 1	0.1, 0.01, 0.3, 0
	$R_2^{\text{dark}(1)}({\text{s}}^{-1})$, residue-specific R2 in dark state 1	200, 20, 1000, 0
	$R_2^{\text{dark}(2)}({\text{s}}^{-1})$, residue-specific R2 in dark state 2	5000, 1000, 1e9, 0
7	Fraction of the exchanging species in NMR-visible state	0.90, 0.01, 0.99, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, sum of on-rates to the dark states usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	Fraction of the exchanging species in dark state 1	0.1, 0.01, 0.3, 0
	k3 (s−1), rate constant from dark state 1 to dark state 2	0.1, 1e–6, 1e6, 0
	$R_2^{\text{dark}(1)}({\text{s}}^{-1})$, residue-specific R2 in dark state 1	200, 20, 1000, 0
	$R_2^{\text{dark}(2)}({\text{s}}^{-1})$, residue-specific R2 in dark state 2	5000, 1000, 1e9, 0
−1	Fraction of population in large R2 (direct-contact) states when bound	0.01, 0.01, 1.0, 0
	$k_{\text{on}}^{\text{app}}({\text{s}}^{-1})$, on-rate to the dark state usually set to the maximum observed ΔR2	3.15, 1.2, 3.15, 0
	Offset (Hz) of dipolar-coupled spin from observed spin	2400, 0, 2500, 1
	koff (s−1), off-rate from the dark state	70, 1e–6, 1e6, 0
	$R_2^{\text{large}}({\text{s}}^{-1})$, R2 in direct-contact population fraction	20000, 50, 1e9, 0
	$R_2^{\text{small}}({\text{s}}^{-1})$, R2 in mobile or tethered population fraction	10, 5, 50, 0