Figure 4.

FTIR spectra comparing the CO complexes formed for PHM WT and variant M314H in the presence and absence of peptide substrate Ac-YVG. (a) WT PHM-CO complexed with substrate (green) and without substrate (black). (b) PHM M314H-CO complexed with substrate (red) and without substrate (black). Spectra are normalized to the intensity of the CO band at 2092 cm−1 and 2075 cm−1 for WT and M314H respectively in the absence of substrate. In the presence of substrate, WT was normalized to 2063 cm−1 and M314H normalized to 2052 cm−1.