Magnetic hyperfine-tensor components, given in Gauss units, for the TOAC-labeled Ctx(Ile21)-Ha analogues used in the nonlinear least-squares fits to the ESR spectra obtained at 22°C.

Observations.•The components of magnetic g-tensor used in the nonlinear least-squares simulations for all the TOAC-containing peptides were: gxx = 2.0096, gyy = 2.0067 and gzz = 2.0036.•TOAC0 derivative incorporated into LPC micelles presented two spectral components. Populations: site 1 (40%), site 2 (60%). Uncertainty: 2%.•The experimental isotropic hyperfine coupling was calculated from the corresponding ESR spectra at 50°C.•A0 was calculated as with the A-tensor values obtained from nonlinear least-squares simulations.•Uncertainty of the A-tensor component values: Axx (5%), Ayy (5%), Azz (2%).