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Unusual features for zirconium(IV) binding to human serum transferrin
- Source :
- JBIC Journal of Biological Inorganic Chemistry. 7:589-599
- Publication Year :
- 2002
- Publisher :
- Springer Science and Business Media LLC, 2002.
-
Abstract
- Human serum apotransferrin (hTF) binds to Zr(IV) slowly in the presence of nitrilotriacetate (NTA), citrate or ethylenediaminetetraacetate (EDTA) as donor ligands. For Zr(NTA)(2)(2-) as donor, equilibrium was reached in ca. 2 h (pH 7.4, 298 K, 10 mM Hepes, 5 mM bicarbonate) and full loading of the N- and C-lobe sites was achievable to give Zr(2)-hTF. (13)C NMR data suggest that carbonate can bind as a synergistic anion. (1)H and 2D [(1)H,(13)C] (using epsilon-[(13)C]Met-hTF) NMR studies show that there is little lobe-selectively in the order of Zr(IV) uptake. Fe(III) displaced Zr(IV) from the C-lobe of Zr(2)-hTF first, followed by the N-lobe. However, in the presence of a large excess of NTA, Zr(IV) binds to the N-lobe of holo-hTF (Fe(2)-hTF) first followed by the C-lobe. The (1)H and (13)C NMR chemical shift changes for epsilon-[(13)CH(3)] of Met464, which is close to the C-lobe site, are quite distinct from those observed previously for Al(III), Fe(III), Ti(IV), Ga(III) and Bi(III) binding to hTF, suggesting that Zr(IV) binding may not induce lobe closure [as observed previously for Hf(IV)]. This may affect receptor recognition and play a role in the different biological behaviour of Zr(IV) compared to Ti(IV).
- Subjects :
- Protein Conformation
Bicarbonate
Inorganic chemistry
Kinetics
chemistry.chemical_element
Ligands
Binding, Competitive
Ferric Compounds
Biochemistry
Medicinal chemistry
Inorganic Chemistry
chemistry.chemical_compound
Spectrophotometry
medicine
Humans
Binding site
Nuclear Magnetic Resonance, Biomolecular
chemistry.chemical_classification
HEPES
Zirconium
Binding Sites
medicine.diagnostic_test
Spectrophotometry, Atomic
Transferrin
Carbon-13 NMR
Recombinant Proteins
chemistry
Spectrophotometry, Ultraviolet
Subjects
Details
- ISSN :
- 14321327 and 09498257
- Volume :
- 7
- Database :
- OpenAIRE
- Journal :
- JBIC Journal of Biological Inorganic Chemistry
- Accession number :
- edsair.doi.dedup.....3295cbdd17713130c3f1438b90613241