THE IRON BINDING-SITES OF CHICKEN OVOTRANSFERRIN

P.F. LINDLEY; R.W. EVANS; R.C. GARRATT; S.S. HASNAIN

doi:doi:10.1051/jphyscol:19868233

EXAFS and Near Edge Structure IV

J. Phys. Colloques 47 (1986) C8-1189-C8-1192
DOI: 10.1051/jphyscol:19868233

THE IRON BINDING-SITES OF CHICKEN OVOTRANSFERRIN

P.F. LINDLEY¹, R.W. EVANS², R.C. GARRATT^{1, 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

Abstract
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 [1]. 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.