[1H,13C] NMR determination of the order of lobe loading of human transferrin with iron: comparison with other metal ions.
Related Articles [1H,13C] NMR determination of the order of lobe loading of human transferrin with iron: comparison with other metal ions.
FEBS Lett. 1998 Feb 6;422(3):315-20
Authors: Sun H, Cox MC, Li H, Mason AB, Woodworth RC, Sadler PJ
Human serum transferrin (hTF) is a single-chain bilobal glycoprotein (80 kDa) which transports Fe3+ and a variety of other metal ions in blood. Only diferric transferrin, not the apo-protein, binds strongly to transferrin receptors and is taken up by cells via receptor-mediated endocytosis. We show here that 2D [1H,13C] NMR studies of recombinant epsilon-[13C]Met-hTF allow the order of lobe loading with various metal ions, including Fe3+, to be determined. In particular, the resonance for Met-464, a residue in the hydrophobic patch of helix 5, is very sensitive to iron binding in the C-lobe. The selectivity of lobe loading with Fe3+ is compared to loading with Fe2+ (which binds as Fe3+), Al3+, Ga3+ and Bi3+. Similar changes in shifts of the Met residues are observed for these metal ions, suggesting that they induce similar conformational changes in the protein.
PMID: 9498807 [PubMed - indexed for MEDLINE]
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PubMed