ALUMINUM SITE STRUCTURE IN SERUM TRANSFERRIN AND LACTOFERRIN REVEALEDBY SYNCHROTRON-RADIATION X-RAY SPECTROSCOPY

The Al site structure of serum transferrin and lactoferrin is investig ated using X-ray absorption near edge structure (XANES) spectroscopy, Al K-edge spectra in the mono-and dialuminum forms of the proteins hav e been recorded for the first time. Our results show that the aluminiu m ion is hexa-coordinated in an octahedral-like symmetry and that the monoaluminum form, where only the C-terminal binding site is saturated , has an increased structural distortion around the metal site.