Exploring the Fe(III) binding sites of human serum transferrin with EPR at 275 GHz
Author(s)
Mathies, Guinevere; Gast, Peter; Chasteen, N. Dennis; Luck, Ashley N.; Mason, Anne B.; Groenen, Edgar J. J.; ... Show more Show less
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We report 275 GHz EPR spectra of human serum transferrin. At this high microwave frequency the zero-field splitting between the magnetic sublevels of the high-spin Fe3+Fe3+ sites can be accurately determined. We find the zero-field splitting to be a sensitive probe of the structure of the transferrin iron-binding sites. Signals arising from iron bound to the transferrin N-lobe can clearly be distinguished from signals from iron bound to the C-lobe. Moreover, our spectra show that the structure of the iron site in the N-lobe is influenced by the presence and conformation of the C-lobe. The spectra of a series of N-lobe mutants altering the second-shell interaction of Arg124 with the synergistic anion carbonate reflect conformational changes induced at the iron site.
Date issued
2014-12Department
Massachusetts Institute of Technology. Department of Chemistry; Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology)Journal
JBIC Journal of Biological Inorganic Chemistry
Publisher
Springer Berlin Heidelberg
Citation
Mathies, Guinevere, Peter Gast, N. Dennis Chasteen, Ashley N. Luck, Anne B. Mason, and Edgar J. J. Groenen. “Exploring the Fe(III) Binding Sites of Human Serum Transferrin with EPR at 275 GHz.” JBIC Journal of Biological Inorganic Chemistry 20, no. 3 (December 24, 2014): 487–496.
Version: Author's final manuscript
ISSN
0949-8257
1432-1327