The mechanism of iron uptake by transferrins: the structure of an 18 kDa NII-domain fragment from duck ovotransferrin at 2.3 A resolution.Lindley, P.F., Bajaj, M., Evans, R.W., Garratt, R.C., Hasnain, S.S., Jhoti, H., Kuser, P., Neu, M., Patel, K., Sarra, R., Strange, R., Walton, A.
(1993) Acta Crystallogr.,Sect.D 49: 292-304
- PubMed: 15299534
- DOI: 10.1107/S0907444992012101
- PubMed Abstract:
- Molecular Structure of Serum Transferrin at 3.3 Angstroms Resolution
Bailey, S.,Evans, R.W.,Garratt, R.C.,Gorinsky, B.,Hasnain, S.,Horsburgh, C.,Jhoti, H.,Lindley, P.F.,Mydin, A.,Sarra, R.,Watson, J.L.
(1988) Biochemistry 27: 5804
- New Perspectives on the Structure and Function of Transferrins
Baker, E.N.,Lindley, P.F.
(1992) J.Inorg.Biochem. 47: 147
- High-Resolution X-Ray Studies on Rabbit Serum Transferrin-Preliminary Structure Analysis of the N-Terminal Half-Molecule at 2.3 Angstroms Resolution
Sarra, R.,Garratt, R.,Gorinsky, B.,Jhoti, H.,Lindley, P.
(1990) Acta Crystallogr.,Sect.B 46: 763
The molecular structure of an iron-containing 18 kDa fragment of duck ovotransferrin, obtained by proteolysis of the intact protein, has been elucidated by protein crystallographic techniques at 2.3 A resolution. This structure supports a mechanism o ...
The molecular structure of an iron-containing 18 kDa fragment of duck ovotransferrin, obtained by proteolysis of the intact protein, has been elucidated by protein crystallographic techniques at 2.3 A resolution. This structure supports a mechanism of iron uptake in the intact protein whereby the binding of the synergistic (bi)carbonate anion is followed by binding of the metal with the lobe in the open configuration. These stages are then followed by domain closure in which the aspartic acid residue plays a further key role, by forming an interdomain hydrogen-bond interaction in addition to serving as a ligand to the iron. This essential dual role is highlighted by model building studies on the C-terminal lobe of a known human variant. In this variant a mutation of a glycine by an arginine residue enables the aspartic acid to form an ion pair and reduce its effectiveness for both metal binding and domain closure. The X-ray structure of the 18 kDa fragment strongly suggests that the histidine residue present at the iron binding site of the intact protein and arising from the second interdomain connecting strand has been removed during the preparative proteolysis.
SERC Daresbury Laboratory, Warrington, Cheshire, England.