J. Phys. Colloques 47 (1986) C8-1189-C8-1192
THE IRON BINDING-SITES OF CHICKEN OVOTRANSFERRINP.F. LINDLEY1, R.W. EVANS2, R.C. GARRATT1, 2 et S.S. HASNAIN3
1 Department of Crystallography, Birkbeck College, Malet Street, GB-London WC1E 7HX, Great-Britain
2 Division of Biochemistry, UMDS, Guy's Hospital St Thomas's Street, GB-London SE1 9RT, Great-Britain
3 SERC Daresbury Laboratory, GB-Warrington WA4 4AD Great-Britain
We have shown previously that the EXAFS spectrum of diferric chicken ovotransferrin (Fe2COT) can only be adequately simulated assuming a split first shell co-ordination . EXAFS and XANES spectra of Fe2COT measured in solution and as a freeze-dried powder provide evidence for perturbation of the iron-binding sites on freeze-drying which involves the loss of one of the long (~2.04 Å) first shell ligands (presumably water). Measurement of the XANES of the C-terminal monoferric COT and a C-terminal domain fragment suggests that the metal binding site remains largely unperturbed by the fragmentation process. The possibility of site interaction is briefly discussed.