Spectral characterization of CYP51_Tc and CYP51_Tb.

<p>Soret and visible regions of the CYP51_Tc (<b>A</b>) and CYP51_Tb (<b>B</b>) spectra are shown. The ferric protein (dashed trace) was reduced with sodium dithionite to a ferrous form (solid trace) in the presence of CO. The spectra were recorded at room temperature in a 1 ml quartz cuvette containing 1 µM CYP51 in 10 mM Tris-HCl, pH 7.5, and 10% glycerol using a Cary UV-visible scanning spectrophotometer (Varian). CYP51_Tc has a Soret maximum at 420 nm which upon reduction with sodium dithionite and CO binding shifts to 449 nm (<b>A</b>). CYP51_Tb has a Soret maximum at 417 nm which upon reduction and CO binding shifts to 446 nm (<b>B</b>).