Iron entry route in horse spleen apoferritin

FEBS Letters

Stefanini, S.³  Petruzzelli, R.¹  Desideri, A.²  Chiancone, E.³  Polizio, F.¹ 

[1]Department of Biology, University of Rome ‘Tor Vergata’, 00173 Rome, Italy

[2]Department of Organic and Biological Chemistry University of Messina, 98166 Messina, Italy

[3]Department of Biochemical Sciences, CNR Center of Molecular Biology, University of Rome ‘La Sapienza’, 00185 Rome, Italy

关键词: Apoferritin: Iron binding site: Spin label: EPR spectroscopy;   

DOI  :  10.1016/0014-5793(91)80004-M

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Apoferritin has been selectively labeled with a maleimide nitroxide derivative at Cys-126, located in the hydrophilic 3-fold channels. Titration of this derivative with Fe(II), which gives rise to the initial Fe(III)-apoferritin complex, produces, at low metal-to-protein ratios, a decrease of the intensity of the label EPR signal due to the occurrence of a magnetic dipolar interaction. A label-metal distance ranging between 8–12 Å can be estimated from titrations performed with VO(IV), which is known to bind in the 3-fold channels, and likewise produces a decrease in the label EPR signal. The present findings indicate that iron binds in the hydrophilic channels in its higher oxidation slate and that these channels represent the metal entry route at least at low metal-to-protein ratios.

【 授权许可】

Unknown