FepB-6His characterization.

<p>A and C: UV-visible spectra of apo-FepB (gray line) and FepB-hemin or FepB-PPIX complex of 2.2 mM (black line). B and D: Spectroscopic measure of hemin and PPIX binding to apo-FepB-6His. Aliquots of hemin or PPIX solutions were successively added to 0.5 ml of apo-FepB-6His (2.22 µM). Absorbance at the Soret bands (404 nm and 407 nm for hemin and PPIX respectively) were reported versus porphyrin concentration corrected for absorbance of free porphyrin at the same concentration. Experiments were done 5 times giving similar curves.