title: Evidence for synergistic anion binding to iron in ovotransferrin complexes from resonance Raman and extended X-ray absorption fine structure analysis.
abstract: The 2,3-dihydroxybenzoate and thioglycolate complexes of iron(III)-ovotransferrin have been studied with resonance Raman and extended x-ray absorption fine structure spectroscopies, respectively, to obtain evidence for the coordination of the synergistic anion to the iron center. The dihydroxybenzoate complex exhibits resonance-enhanced Raman vibrations arising from both the endogenous tyrosinates and the added dihydroxybenzoate. A comparison of the extended x-ray absorption fine structure spectra of the carbonate and thioglycolate complexes shows a large feature at about 1.95 A assigned to Fe-(O,N) interactions. The latter complex exhibits an added feature at 2.32 A assigned to an Fe-S interaction. These experiments demonstrate that the Lewis base functions in the synergistic anions coordinate to the iron in ovotransferrin.
mesh_terms: D003207:Conalbumin / Q000378:metabolism*; D004527:Egg Proteins / Q000378:metabolism*; D005583:Fourier Analysis; D062385:Hydroxybenzoates / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008433:Mathematics; D013053:Spectrophotometry; D013057:Spectrum Analysis; D013059:Spectrum Analysis, Raman; D013864:Thioglycolates / Q000378:metabolism*; D014965:X-Rays
chemical_list: D004527:Egg Proteins; D062385:Hydroxybenzoates; D013864:Thioglycolates; D003207:Conalbumin; C009135:2,3-dihydroxybenzoic acid; D007501:Iron