Interprobe distances in the labeled CYP3A4 derivatives*.

*The values given in the table represent the averages of at least 10 individual measurements, and the ± values show the confidence interval calculated for p = 0.05.aDistances observed in the PDB structure 1W0F. The distances were measured between the sulfur atoms of cysteines, except for C64/C121, where the value correspond to the distance between the sulfur atom of Cys64 and C-beta carbon of alanine (which is the native residue at this position).bEfficiency of LRET. In the case of steady-state measurements these values were calculated from the spectra of delayed emission according to Eq. 1. For the lifetime measurements the calculations were done with Eq. 2 using the values of τd (lifetime in the absence of acceptor) determined with the respective mutants labeled with ERIA only (see Table S1.