title: Low-temperature electron paramagnetic resonance study of the ferricytochrome c-cardiolipin complex.
abstract: The electron paramagnetic resonance spectrum of the ferricytochrome c complex with cardiolipin was observed at temperatures below 20 K. For the low-spin iron(III) heme system complexed with the negatively charged lipid, the tetragonal and rhombic ligand field parameters (delta/lambda = 3.58, V/lambda = 1.82) differ significantly from those (delta/lambda = 2.53, V/lambda = 1.49) of the free ferricytochrome c sample. The g values of the complex (gx = 1.54 +/- 0.02, gy = 2.26 +/- 0.01, gz = 3.02 +/- 0.01) are compared to the values for free ferricytochrome c (gx = 1.25 +/- 0.02, gy = 2.25 +/- 0.01, gz = 3.04 +/- 0.01). Spectral alterations are interpreted in terms of the ligand field changes induced within the heme group by association with the negatively charged phosphoglyceride.
mesh_terms: D002308:Cardiolipins / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005615:Freezing; D008024:Ligands; D011485:Protein Binding
chemical_list: D002308:Cardiolipins; D003574:Cytochrome c Group; D008024:Ligands