TABLE 1.

Best-fit parameters from NLLS simulations of the EPR spectra obtained from mixtures of the enzyme Pp 1,2-CCD and several spin labels

	Label	Axx†	Ayy	Azz	A0‡	R⊥ (109 s−1)	ΔG (Gauss)
(A) Pure label	CAT16	6.5	5.5	38.8	16.9	2.50	1.4
	5-SASL	6.5	5.5	35.4	15.8	0.88	1.3
	12-SASL	6.5	5.5	35.7	15.9	0.77	1.3
	16-SASL	6.5	5.5	35.6	15.9	0.91	1.3
(B) SL/CCD = 1:4	CAT16	6.5	5.6	38.3	16.8	0.077	0*
	5-SASL	6.3	5.9	34.6	15.6	0.019	2.1
	12-SASL	6.1	5.0	32.1	14.4	0.012	3.7
	16-SASL	6.0	5.5	33.6	15.0	0.020	3.5
(C)PCSL/CCD = 1:2	5-PC	6.3	5.5	34.8	15.5	0.020	3.3
	7-PC	6.3	6.3	33.5	15.4	0.017	3.7
	10-PC	6.5	6.5	31.5	14.8	0.006	3.2
	12-PC	6.6	6.6	31.9	15.0	0.012	4.7
	16-PC	6.6	6.5	33.2	15.4	0.018	2.4

The magnetic g-tensor components used in the fits were g_xx = 2.0086, g_yy = 2.0063, g_zz = 2.0025 (Ge et al., 1990).

^*Very small values, so kept fixed at 0.

^†A-tensor components are in Gauss.

^‡A₀ = (A_xx + A_yy + A_zz)/3.

Estimated errors: R_⊥ (5%); A_xx and A_yy (10%); A_zz (5%); and Δ_G (10%).