Metal and anion binding sites in lactoferrin and related proteins

Abstract

The metal and anion binding sites of the protein lactoferrin (Lf) have been defined through crystallographic analyses of Fe2Lf and Cu2Lf. In both cases each metal ion is 6-coordinate, with four protein ligands (2 Tyr, 1 Asp, 1 His) and the synergistic CO32-anion which binds as a bidentate ligand. The C032- fits into a pocket between the metal and the N-terminus of an a-helix. Binding of other metals and anions can be understood in terms of the protein structure and a suggested mechanism for binding and release. Differences between the two sites in Lf can also be explained. Striking similarities between Lf and a SO42- binding protein suggest links between bacterial and mammalian binding proteins. © 1990 IUPAC