title: The linear electric field effect in stellacyanin, azurin and in some simple model compounds.
abstract: All mononuclear Cu(II) sites in frozen solution are non-centrosymmetric and, unless physically constrained, will have a tetrahedral distortion away from the usual square planar structure often presented for Cu(II) complexes. Blue copper sites such as are found in azurin and stellacyanin have a greater distortion towards a tetrahedral geometry than do simple Cu(II) complexes. The distortion is comparable to that which is observed for Cu(II)-o-phenanthroline dichloride, a known tetrahedral complex. Blue copper sites possess an axis of asymmetry directed away from g parallel which could arise from a metal-sulfur interaction.
mesh_terms: D001400:Azurin; D001426:Bacterial Proteins; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper; D004578:Electron Spin Resonance Spectroscopy; D008667:Metalloproteins; D010940:Plant Proteins; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; D010940:Plant Proteins; D001400:Azurin; C003343:stellacyanin protein, plant; D003300:Copper