1aiv
From Proteopedia
APO OVOTRANSFERRIN
Structural highlights
Function[TRFE_CHICK] Transferrins are iron binding transport proteins which can bind two Fe(3+) ions in association with the binding of an anion, usually bicarbonate. Responsible for the transport of iron from sites of absorption and heme degradation to those of storage and utilization. There are two forms of hen transferrin, ovotransferrin, found in the ovoducts and, serum transferrin, secreted by the liver. Serum transferrin may also have a role in stimulating cell proliferation and is regulated by iron levels. Ovotransferrin has a bacteriostatic function and, is not controlled by iron levels. 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 three-dimensional crystal structure of hen apo-ovotransferrin has been solved by molecular replacement and refined by simulated annealing and restrained least squares to a 3.0-A resolution. The final model, which comprises 5312 protein atoms (residues 1 to 686) and 28 carbohydrate atoms (from two monosaccharides attached to Asn(473)), gives an R-factor of 0.231 for the 11,989 observed reflections between 20.0- and 3.0-A resolution. In the structure, both empty iron binding clefts are in the open conformation, lending weight to the theory that Fe(3+) binding or release in transferrin proceeds via a mechanism that involves domain opening and closure. Upon opening, the domains rotate essentially as rigid bodies. The two domains of the N-lobe rotate away from one another by 53 degrees, whereas the C-lobe domains rotate away each another by 35 degrees. These rotations take place about an axis that passes through the two beta-strands, linking the domains. The domains of each lobe make different contacts with one another in the open and closed forms. These contacts form two interdomain interfaces on either side of the rotation axis, and domain opening or closing produces a see-saw motion between these two alternative close-packed interfaces. The interdomain disulfide bridge (Cys(478)-Cys(671)), found only in the C-lobe, may restrict domain opening but does not completely prevent it. Crystal structure of hen apo-ovotransferrin. Both lobes adopt an open conformation upon loss of iron.,Kurokawa H, Dewan JC, Mikami B, Sacchettini JC, Hirose M J Biol Chem. 1999 Oct 1;274(40):28445-52. PMID:10497206[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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