title: Spectroscopic studies on bleomycin-iron complexes with carbon monoxide, nitric oxide, isocyanide, azide, and cyanide and comparison with iron-porphyrin complexes.
abstract: The bleomycin-iron complexes with CO, NO, C2H5NC, OH-, N-3, CN-, and CH3NH2 were characterized by electronic, ESR, 1H-NMR, and Mössbauer spectroscopies and the findings were compared with the corresponding hemoprotein complexes. The 1H-NMR and Mössbauer features for the CO and C2H5NC adducts of the bleomycin-Fe(II) complex are consistent with an S = 0 ferrous assignment. The OH-, CH3NH2, and N-3 adducts of the bleomycin-Fe(III) complex show the ESR, 1H-NMR, and Mössbauer spectra typical of a low-spin Fe(III). The unique Mössbauer parameters of the bleomycin-Fe(II)-NO complex demonstrate mixing between the NO pi- and the Fe 3d-orbitals. The magnitude of the proton chemical shifts over +/- 50 ppm indicates a high-spin ferric type for the bleomycin-Fe(III)-CN complex. The Mössbauer parameters (delta EQ = 0.89 and delta = 0.48 mm/s) of the CN- adduct differ substantially from those of typical low-spin hemoprotein-cyanide complexes. Except for the CN- adduct, the Mössbauer and crystal field parameters of these bleomycin-iron complexes are similar to those of the corresponding hemoprotein complexes.
mesh_terms: D001386:Azides / Q000378:metabolism*; D001761:Bleomycin / Q000378:metabolism* / Q000494:pharmacology; D002248:Carbon Monoxide / Q000378:metabolism*; D003486:Cyanides / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D006418:Heme / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009569:Nitric Oxide / Q000378:metabolism*; D009570:Nitriles / Q000378:metabolism; D010084:Oxidation-Reduction; D013051:Spectrometry, Gamma
chemical_list: D001386:Azides; D003486:Cyanides; D009570:Nitriles; D001761:Bleomycin; D009569:Nitric Oxide; D006418:Heme; C001187:ethyl isocyanide; D002248:Carbon Monoxide; D004247:DNA; D007501:Iron