Table 1.

Intrinsic copper-free T₁ values and interspin distances measured for four TAM1-spin labeled mutants of T4 Lysozyme, and modeled interspin distances (See Figure 2).

T4 Lysozyme Mutanta	Intrinsic T1, $T_{1s}^0$ (μs)b	Interspin Distance, r (Å)	Modeled Distance (Å)
23L/131TAM1	12.0	37.9	39.5
23L/131TAM1 (p-AcPhe at 65)	12.5	37.7	39.5
37L/76TAM1	12.1	32.6	35.1
135L/76TAM1	12.1	32.8	36.1

^aAll proteins immobilized via random attachment to CNBr-activated Sepharose solid support, except for the sample labeled ‘p-AcPhe at 65’, which was site-specifically attached via biotin linkage.

^bReported intrinsic T₁ values obtained by measuring copper-free T₁ values at various observe powers with extrapolation to zero power; complete data in Supporting Information.