PMID: 15972819 , Related PDB ids: 1ZT3, 1ZT5

Authors:

Sala A, Capaldi S, Campagnoli M, Faggion B, Labo S, Perduca M, Romano A, Carrizo ME, Valli M, Visai L, Minchiotti L, Galliano M, Monaco HL

Title:

Structure and properties of the C-terminal domain of insulin-like growth factor-binding protein-1 isolated from human amniotic fluid.

Journal:

J Biol Chem. 2005 Aug 19;280(33):29812-9. Epub 2005 Jun 22.

Abstract:

Insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) regulates the activity of the insulin-like growth factors in early pregnancy and is, thus, thought to play a key role at the fetal-maternal interface. The C-terminal domain of IGFBP-1 and three isoforms of the intact protein were isolated from human amniotic fluid, and sequencing of the four N-terminal polypeptide chains showed them to be highly pure. The addition of both intact IGFBP-1 and its C-terminal fragment to cultured fibroblasts has a similar stimulating effect on cell migration, and therefore, the domain has a biological activity on its own. The three-dimensional structure of the C-terminal domain was determined by x-ray crystallography to 1.8 Angstroms resolution. The fragment folds as a thyroglobulin type I domain and was found to bind the Fe(2+) ion in the crystals through the only histidine residue present in the polypeptide chain. Iron (II) decreases the binding of intact IGFBP-1 and the C-terminal domain to IGF-II, suggesting that the metal binding site is close to or part of the surface of interaction of the two molecules.