1fck

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spinqualitylabelsall models 1fck, resolution 2.2Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF DICERIC HUMAN LACTOFERRIN

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

Proteins of the transferrin family play a key role in iron homeostasis, through their extremely strong binding of iron, as Fe3+. They are, nevertheless able to bind a surprisingly wide variety of other metal ions., To investigate how metal ions of different size, charge and coordination, characteristics are accommodated, we have determined the crystal structure, of human lactoferrin (Lf) complexed with Ce4+. The structure, refined at, 2.2 A resolution (R=20.2%, Rfree=25.7%) shows that the two Ce4+ ions, occupy essentially the same positions as do Fe3+, and that the overall, protein structure is unchanged; the same closed structure is formed for, Ce2Lf as for Fe2Lf. The larger metal ion is accommodated by small shifts, in the protein ligands, made possible by the presence of water molecules, adjacent to each binding site. The two Ce4+ sites are equally occupied, indicating that the known difference in the pH-dependent release of Ce4+, arises from a specific protonation event, possibly of the His ligand in, one of the binding sites. Comparing the effects of binding Ce4+ with those, for the binding of other metal ions, we conclude that the ability of, transferrins to accommodate metal ions other than Fe3+ depends on an, interplay of charge, size, coordination and geometrical preferences of the, bound metal ion. However, it is the ability to accept the six-coordinate, approximately octahedral, site provided by the protein that is of greatest, importance.

Disease

Known disease associated with this structure: Deafness, autosomal dominant 1 OMIM:[602121]

About this Structure

1FCK is a Single protein structure of sequence from Homo sapiens with CO3 and CE as ligands. Full crystallographic information is available from OCA.

Reference

Metal substitution in transferrins: specific binding of cerium(IV) revealed by the crystal structure of cerium-substituted human lactoferrin., Baker HM, Baker CJ, Smith CA, Baker EN, J Biol Inorg Chem. 2000 Dec;5(6):692-8. PMID:11128996

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