Figure 5.

Analysis of pressure-induced changes in the EPR spectra of CYP3A4(C85)R1 by PCA. (a) Normalized EPR spectra were obtained at pressures of 1 bar and 1, 2, and 3 kbar. The inset shows the spectra of the first (solid line) and second (dashed line) PCs of the observed changes. (b) Pressure dependencies of the loading factors for the first (circles) and second (triangles) PCs. Dashed lines show the approximations of the data sets with Eq. 4 using the values of ΔV° and P_1/2 determined in the studies with CYP3A4(C85)MDCC. In the case of the first PC, these parameters represent a pressure-induced solvatochromic shift, whereas in the case of the second PC, we used values characterizing the pressure dependence of fluorescence intensity. Solid lines show the results obtained by optimizing these parameters for the best fitting of the data sets.