Abstract
The polypeptide chain that assembles into the unusual dodecameric shell of Listeria innocua apoferritin lacks the ferroxidase centre characteristic of H-type mammalian chains, but is able to catalyse both Fe(II) oxidation and nucleation of the iron core. A cluster of five carboxylate residues, which correspond in part to the site of iron core nucleation typical of L-type mammalian ferritins, has been proposed to be involved in both functions. The features of the iron uptake kinetics and of Fe(II) autoxidation in the presence of citrate followed spectrophotometrically confirm this assignment. In Listeria the kinetics of iron uptake is hyperbolic at low Fe(II)-to-dodecamer ratios and becomes sigmoidal when iron exceeds 150 Fe(II) atoms per dodecamer, namely when a fast crystal growth phase follows a slow initial nucleation step. Iron autoxidation in the presence of citrate displays a similar behaviour. Thus the time course is sigmoidal at low citrate-to-Fe ratios at which Fe(III) polymerization is predominant, but is hyperbolic at ligand concentrations high enough to prevent polymerization. The marked inhibitory effect of Tb(III) on the kinetics of iron incorporation confirms that carboxylates provide the iron ligands in L. innocua apoferritin. Iron uptake followed in steady-state fluorescence experiments allows one to distinguish Fe(II) binding and oxidation from the subsequent movement of Fe(III) into the apoferritin cavity as in mammalian ferritins despite the different localization of the tryptophan residues.
Full Text
The Full Text of this article is available as a PDF (130.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BOTHWELL T. H., MALLETT B. The determination of iron in plasma or serum. Biochem J. 1955 Apr;59(4):599–602. doi: 10.1042/bj0590599. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bozzi M., Mignogna G., Stefanini S., Barra D., Longhi C., Valenti P., Chiancone E. A novel non-heme iron-binding ferritin related to the DNA-binding proteins of the Dps family in Listeria innocua. J Biol Chem. 1997 Feb 7;272(6):3259–3265. doi: 10.1074/jbc.272.6.3259. [DOI] [PubMed] [Google Scholar]
- Cavallo S., Mei G., Stefanini S., Rosato N., Finazzi-Agrò A., Chiancone E. Formation and movement of Fe(III) in horse spleen, H- and L-recombinant ferritins. A fluorescence study. Protein Sci. 1998 Feb;7(2):427–432. doi: 10.1002/pro.5560070224. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grant R. A., Filman D. J., Finkel S. E., Kolter R., Hogle J. M. The crystal structure of Dps, a ferritin homolog that binds and protects DNA. Nat Struct Biol. 1998 Apr;5(4):294–303. doi: 10.1038/nsb0498-294. [DOI] [PubMed] [Google Scholar]
- Harris D. C., Aisen P. Facilitation of Fe(II) autoxidation by Fe(3) complexing agents. Biochim Biophys Acta. 1973 Nov 2;329(1):156–158. doi: 10.1016/0304-4165(73)90019-6. [DOI] [PubMed] [Google Scholar]
- Harrison P. M., Arosio P. The ferritins: molecular properties, iron storage function and cellular regulation. Biochim Biophys Acta. 1996 Jul 31;1275(3):161–203. doi: 10.1016/0005-2728(96)00022-9. [DOI] [PubMed] [Google Scholar]
- Levi S., Luzzago A., Cesareni G., Cozzi A., Franceschinelli F., Albertini A., Arosio P. Mechanism of ferritin iron uptake: activity of the H-chain and deletion mapping of the ferro-oxidase site. A study of iron uptake and ferro-oxidase activity of human liver, recombinant H-chain ferritins, and of two H-chain deletion mutants. J Biol Chem. 1988 Dec 5;263(34):18086–18092. [PubMed] [Google Scholar]
- Levi S., Santambrogio P., Corsi B., Cozzi A., Arosio P. Evidence that residues exposed on the three-fold channels have active roles in the mechanism of ferritin iron incorporation. Biochem J. 1996 Jul 15;317(Pt 2):467–473. doi: 10.1042/bj3170467. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Macara I. G., Hoy T. G., Harrison P. M. The formation of ferritin from apoferritin. Kinetics and mechanism of iron uptake. Biochem J. 1972 Jan;126(1):151–162. doi: 10.1042/bj1260151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martin R. B., Richardson F. S. Lanthanides as probes for calcium in biological systems. Q Rev Biophys. 1979 May;12(2):181–209. doi: 10.1017/s0033583500002754. [DOI] [PubMed] [Google Scholar]
- Saviotti M. L., Galley W. C. Room temperature phosphorescence and the dynamic aspects of protein structure. Proc Natl Acad Sci U S A. 1974 Oct;71(10):4154–4158. doi: 10.1073/pnas.71.10.4154. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stefanini S., Chiancone E., Antonini E., Finazzi-Agro A. Binding of terbium to apoferritin: a fluorescence study. Arch Biochem Biophys. 1983 Apr 15;222(2):430–434. doi: 10.1016/0003-9861(83)90541-6. [DOI] [PubMed] [Google Scholar]
- Sun S., Arosio P., Levi S., Chasteen N. D. Ferroxidase kinetics of human liver apoferritin, recombinant H-chain apoferritin, and site-directed mutants. Biochemistry. 1993 Sep 14;32(36):9362–9369. doi: 10.1021/bi00087a015. [DOI] [PubMed] [Google Scholar]
- Sun S., Chasteen N. D. Ferroxidase kinetics of horse spleen apoferritin. J Biol Chem. 1992 Dec 15;267(35):25160–25166. [PubMed] [Google Scholar]
- Treffry A., Harrison P. M. Spectroscopic studies on the binding of iron, terbium, and zinc by apoferritin. J Inorg Biochem. 1984 May;21(1):9–20. doi: 10.1016/0162-0134(84)85035-7. [DOI] [PubMed] [Google Scholar]