A 57Fe Moessbauer characterization of Fe-biopolymer complexes and their relevance to biological molecules

57Fe Moessbauer spectroscopy is used to study the interactions, geometry, and the coordination characteristics of the Fe-complexes of biopolymers such as chitosan, glucosamine, and chondritin sulfate. In addition, a computational effort is undertaken for predicting the geometries and energies of the metal complexes by the Density Functional Theory (DFT) methods as implemented in the Gaussian 2003 quantum mechanical program. Both experimental and computational results suggest that the structure of the metal complexes resemble closely the structure of the active sites of metalloenzymes in 2+ or 3+ oxidation states and is at least tetracoordinated and can possibly have six ligands.