Table 1.

Spin-Hamiltonian parameters for ⁶³Cu(II)-BlLPMO10A and ⁶³Cu(II)-¹⁵N-BlLPMO10A at pH 5.5 with and without squid pen β-chitin

		63Cu-BlLPMO10A	63Cu-15N-BlLPMO10A		63Cu-BlLPMO10A + β-chitin	63Cu-15N-BlLPMO10A+ β-chitin
		X-band	X-band	Q-band	X-band	X-band	Q-band
g values	g1	2.027	2.029	2.032	2.042	2.038	2.046
	g2	2.095	2.081	2.112	2.053	2.046	2.057
	g3	2.261	2.261	2.260	2.205	2.209	2.208
	giso	2.128	2.124	2.135	2.101	2.098	2.104
ACu, /MHz	|A1|	255	255	255	80	88	80
	|A2|	110	115	115	85	95	90
	|A3|	336	336	340	620	610	610
Calculated*	Aiso	10	11	10	−208 or −262	−205 or −264	−207 or −260
SHF AN principal values,† /MHz		43, 43, 28	60, 60, 40	60, 60, 40	40, 40, 32	56, 56, 45	55, 55, 45
		±5	±5		±2	±2
gCu strains		0, 0.02, 0.007	0, 0.025, 0.005	0, 0.045, 0.007	0.004, 0, 0.007	0.005, 0, 0.009	0.005, 0, 0.003
ACu strains, /MHz		130, 55, 160	160, 60, 160	20, 10, 120	20, 20, 20	10, 10, 10	90, 40, 240
Linewidths		0.6, 0.6	0.6, 0.6	4.5, 4.5	0.4, 0.4	0.5, 0.6	1.3, 1.3
Frequency, /GHz		9.3046	9.2973	35.00	9.2988	9.2884	35.05

For coupled nitrogen nuclei, only the principal coupling value could be determined from the simulations of the superhyperfine (SHF), which we presume is the coupling along the Cu–N bond; the three values in each spectrum refer to three different N nuclei, with the smallest value in each set being assigned to the NH₂.

^*Signs of A₁ and A₂ calculated from DFT (see main text).

^†Error estimated from quality of simulated fits.