MICROPEROXIDASE-11 - MOLECULAR-DYNAMICS AND Q-BAND EXCITED RESONANCE RAMAN OF THE OXIDIZED, REDUCED AND CARBONYL FORMS

Resonance Raman spectra with Q-band excitation are reported for microp eroxidase-l 1, the cytochrome c analog. Spectra were acquired in the m id-frequency range for the oxidized, and reduced forms of the undecape ptide, as well as for the imidazole and carbonyl complexes. Oxidation and spin state marker bands of the undecapeptides are consistent with a six-coordinate, low spin iron in both oxidation states. Porphyrin co re size correlations yield a porphyrin-centre to pyrrole-nitrogen dist ance of 2.00 Angstrom for MP11, suggestive of a six-coordinate species in a distorted heme environment. Molecular dynamics results show that the non-planarity of the heme of the parent cytochrome is conserved i n the microperoxidase and its carbonmonoxy analog.