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THE MECHANISM OF IRON UPTAKE BY TRANSFERRINS: THE STRUCTURE OF AN 18KD NII-DOMAIN FRAGMENT AT 2.3 ANGSTROMS RESOLUTIONTHE MECHANISM OF IRON UPTAKE BY TRANSFERRINS: THE STRUCTURE OF AN 18KD NII-DOMAIN FRAGMENT AT 2.3 ANGSTROMS RESOLUTION
Structural highlights
FunctionTRFE_ANAPL Transferrins are iron binding transport proteins which can bind two Fe(3+) ions in association with the binding of an anion, usually bicarbonate. It is responsible for the transport of iron from sites of absorption and heme degradation to those of storage and utilization. Serum transferrin may also have a further role in stimulating cell proliferation. Ovotransferrin has a bacteriostatic function. Its concentration in avian egg is the highest concentration of any transferrin in vivo (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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. 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 PF, Bajaj M, Evans RW, Garratt RC, Hasnain SS, Jhoti H, Kuser P, Neu M, Patel K, Sarra R, Strange R, Walton A Acta Crystallogr D Biol Crystallogr. 1993 Mar 1;49(Pt 2):292-304. PMID:15299534[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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